Shops on Reeperbahn
You'll find many different clothing stores and souvenir shops at the Reeperbahn. Various St. Pauli T-shirts is among the popular items. On the north-west side of Reeperbahn you'll find a nice second hand like shop with lots of cheap items.
If you're in need of some cheap alcohol we recommend the Lidl super market on the north-west side of Reeperbahn. If you go a little further across a big intersection you'll find Penny Markt, another good super market.