I was hoping to purchase a commemorative silver coin from Estonia. However, the prices in the local coin store in the Old Town were very expensive. As a result, I decided against making any purchases.
The souvenir shops (souveniirid) all carry mostly the same things but vary widely in price. Shop around, its part of the whole charm of the old town. The best prices by far were in the museums. The worst prices were in the shops up on Toompea.