It reminds me Days by James Lovegrove.
Here is one cover of the book:
There is a giant store where you can buy anything. A matchbox, a tiger, a Ferrari, socks, ... The store is quite big as a city and have many levels. Aisles are like streets. You can rent a car to wander among them more easily.
The reader follows the adventures of :
- a woman and her husband in this enormous store for the first time. She's very excited, but the husband is reticent
- a disenchanted security guard on his last day of work
- an employee from the Book department, fomenting a rebellion against the IT department
- the seven brothers, who own the place (the youngest is a source of problems).They live at the top floor of the store and leave it rarely. Their names are based on the seven days of the week. Days is their family name and also the name of the store.
The right amount of credit on your card will buy you anything--a rare
matchbook, an albino tiger, the women in the Pleasure department. Days
is the grandest of department stores, whose security men are licensed
to kill and whose seven owners, a group of very different brothers,
brood in a penthouse, fetched endless vast meals by a grumpy butler.
James Lovegrove's novel inhabits that realm where satire borders on
allegory and realism is full of wild magic; it was, nonetheless,
shortlisted for the Arthur C. Clarke prize. Security man Frank has
reached a point of alienation such that he can no longer see himself
in the mirror; Gordon and Linda have just got their first Days
storecard, and are keen to undergo the Days experience; the Book
Department's feud for space with their neighbours in Computers is
about to enter a new phase. There are flash sales in Ties and Dolls,
and a riot in Third World Musical Instruments. And who is sleeping in
the Bed Department's four- poster? Endlessly inventive and savage in
its humour, Lovegrove's novel will change for ever the way you feel
about superstores, and gives a whole new meaning to the phrase "shop
till you drop". --Roz Kaveney
I don't remember the "no exit" part, but she really gets lost and falls into the exotic animal zone (she met there the albino tiger that many people seem to remember and is for sale, as anything in the store)