The colloquial British-English phrase glad and sorry denotes hire purchase, i.e., a system by which one pays for a thing in regular instalments while having the use of it.
—Synonym: Kathleen Mavourneen.

In the phrase glad and sorry, the image is that the hire-purchaser is at the same time glad to have the use of the merchandise and sorry to still have to pay for it.

These are, in chronological order, the earliest occurrences of the phrase glad and sorry that I have found:

1-: From the column The Lighter Side, published in the Nottingham Evening Post (Nottingham, Nottinghamshire, England) of Monday 6^th May 1929:

Spread of the Hire Purchase.
There are 5,000,000 hire-purchase agreements in the country, involving a capital of £250,000,000. That it has come to stay and spread is shown by the fact that firms of household fame are members of the Association of Hire Traders.
One firm sells aeroplanes on instalments slightly higher than those on motor-cars. From the economist’s point of view the system is sound; to the trader the risk of loss is not 1 per cent.
The Glad and Sorry System.
What of the hire-purchaser himself? He sometimes calls it the “glad and sorry” system—glad he has the goods, sorry he has still to pay for them. He does not legally become owner or even part-owner of the goods until the final and completing instalment is paid.
On the other hand, it is an incentive to giving orders—and saving for the payments. But there is just the risk of the over-persuasive salesman and the too easily persuaded housewife.

2-: From the transcript of a speech on the removal and prevention of slums that T. Lawrence Dale, diocesan architect, delivered at the Deddington Ruridecanal Conference held at Banbury on Saturday 14^th October 1933—transcript published in The Banbury Advertiser (Banbury, Oxfordshire, England) of Thursday 19^th October 1933:

It was stated by Mr. Dale that slums worse than those being destroyed were being erected, and that firms financed by building societies were engaged in exploiting the necessities of poor people who needed houses.
[…]
There were firms financed by building societies engaged in exploiting the necessities of the poor who needed houses, which cost them about £300 or less to produce and who sold them at £600 or more on the hire purchase system, or “Glad and sorry” system, by which the purchaser paid a deposit of £50 or £60, and the balance at five per cent., which was ten per cent on the cost spread over a period of twenty years. But the terrible thing about it was that these houses, owing to the quality of the joinery and the character of the timber would be scarcely tenantable by the end of the repayment period.

3-: From Drama in the Village: Mr. & Mrs. Bright, by Elyn Walshe, published in The Manchester Guardian (Manchester, Lancashire, England) of Wednesday 1^st September 1937:

The Brights have left the village, and their disappearance has made a lot of talk. Their arrival and their sojourn here also caused a good deal of comment. It was so plain that they did not belong to a village.
They were known as the little Brights, because their ages when they first came totalled 35 years. The husband was 18 and the wife 17. They took a nice new house with a lounge and bathroom. […]
[…]
Suddenly the house was empty and they had gone. The village collected information, here a bit and there a bit, and when assembled it amounted to this. These rash children had met in the factory where they both worked, and after a few weeks of walking out, or keeping company, or whatever it was, the boy had got a spectacular rise and they had married. Not having saved a penny, they had furnished on the hire-purchase system—the glad-and-sorry system, the village calls it. […]
[…]
Mrs. Briggs was angry with the furniture people who had swooped down and emptied the house. She accused these traders of tempting the young too greatly. She is for abolishing the glad-and-sorry system by law, at once and for ever. She declared that the Brights had not known how long they would have to go on paying. She had happened to pass just when the furniture was being removed and had seen the little wife and mother with her eyes all swollen with crying and her mouth still orange-coloured and all smeared. Mrs. Briggs’s heart was touched, naturally, but the next-door neighbour who was present affirmed that Mrs. Bright had told her that she could not remember what they had signed. Her dad had insisted on reading the paper out to them one evening at tea, and what with the dance music from the wireless and “Frank” squeezing her hand all the time she had not taken in a word of it. The neighbour gathered that dad had done his best to put sense into them, but his daughter had not reacted favourably at all. Dad was really nasty about “Frank,” she said.
The neighbour maintained that you could hardly blame the furniture people. Mrs. Bright was no housekeeper, and the things were going to rack and ruin. She herself thought it was a good idea, this hire-purchase business. There was her Bert just got a job in the town. They could not buy him a bicycle, and the bus fare was five shillings a week. So Bert got a bicycle, paying three shillings a week, and he had it for evenings and Sundays too. How long had he to go on paying ? She could not say.

4-: From an advertisement for a motorcycle, published in The Bucks Herald (Aylesbury, Buckinghamshire, England) of Friday 6^th June 1952:

B.S.A. 500, good condition, good looker; £30 rides away T. and I; glad and sorry  if required.—Apply 19, Nightingale Road, Southcourt.

5-: From the West London Press (London, England) of Friday 5^th February 1954:

A DUST-CART—ON THE ‘GLAD—AND—SORRY’ . . .

Borrowing £2,128 over a period of ten years for the purchase of a dust-cart was “unorthodox finance,” said Cllr. Dixon (Lab.) at Chelsea Council meeting.
Cllr. Dixon said the case for doing it was that at the present time, although they collected rates to provide the borough’s current “housekeeping needs”—such as the new dust-cart—they should put off paying the bill as long as possible.
He went on, “To dodge prompt payment we are advised to borrow £2,128 and pay the interest on £2,128 for ten years.
“That means we would have to pay about £800 in interest.
“But later on, to avoid having to pay that interest, we will be advised not to borrow the £2,128 after all, but to pay the instalments we would have to pay if we did borrow the money, out of the rates.
“I hope the explanation has got you all thoroughly confused.
“To put it in a nutshell, the Finance Committee want to use the majestic machinery of the Public Works Loans Board in order to get a dust-cart on the ‘glad and sorry,’ and then dodge the hire-purchase interest by lending the money to itself.
“The chief advantage is that it gives the ratepayers the illusion that they haven’t spent £2,128 on a dust-cart!”
Cllr. Lygon, Finance Committee chairman, said his committee agreed that the loan should be spread over a reasonable period and not charged in the accounts of the year of purchase.

6-: From The Birmingham Post (Birmingham, Warwickshire, England) of Saturday 26^th February 1955:

THE POLITICAL SCENE By Our Lobby Correspondent
MR. BUTLER CROSSES THE TIGHT-ROPE

Conservative heads bow once more in respect and admiration at the shrewdness of the Chancellor. […] Mr. Butler has safeguarded the possibility of Budget glamour and preserved election manœuvrability in the autumn.
[…]
[…] From the Prime Minister downwards there is reliance upon his strong leadership, and his writ runs powerfully in the Cabinet and outside. It may be that the “never-never” (or as some have it the “glad and sorry”) restraints are not adequate—for a 15 per cent down payment and a two years’ repayment period are already fairly normal in hire purchase, but the main thing is that it is likely that by the autumn, there will be a surplus in the balance of payments.