Forget it!
Retin-A contains a powerful drug (Tretinoin), which has many known side effects (including thinning of the skin and birth defects). It should only ever be used under medical direction and for the specific conditions which it is designed to treat (such as severe acne). Any source offering it without a prescription will be doing so illegally, with a high risk of the product which is sold actually being a dangerous fake.
The way that skin ages suggests that NO topical treatment (whether that be a cream, gel, lotion or anything else) will EVER be able to get rid of wrinkles
(or the other signs of aging). The best that can be done is simply to hide them. No properly validated study has ever been able to show that ANY such product actually works (or will ever do so in the future). Don't waste your money.
Chris