Sucre has two main supermarkets, Supermercado Pompeya and Supermercado SAS. Of these, Pompeya is the most central, being only 1/2 a block from the central square, Plaza 25 de Mayo.
The entrance to Supermercado Pompeya is at #42 España, which you can find from Plaza 25 de Mayo by locating the corner with Metro Cafe, and taking the street to its left. Half a block along this street on your left you’ll see the entrance with a golden “Pompeya” sign above it. As you enter you’ll see a large stationary shop on you left. Pompeya is straight ahead.
At the entrance to Pompeya are a number of self-serve lockers where you are expected to leave your bags, rather than bringing them in. Beside that are a pile of shopping baskets.
Pompeya is modestly-sized, but serves for most purposes. It sells a good range of drinks both soft and alcoholic. It has a wide range of canned goods, pastas, sauces, etc. It also stocks pretty much everything you might need for the bathroom.
Where Pompeya might let you down is in fresh produce. While it has a fruit and vegetable section at the back right, these are often of quite poor quality. You will find much better fruit and veg at either the SAS supermarket, or the Mercado Central. Pompeya also has only a limited range of bread on offer. Again SAS is the better option for this. There is also very little on offer in terms of meat (other than pre-packaged hamburgers, sausages, etc).
Pompeya Supermarket is a very useful place to know, mainly for its central location. Whenever you just need to pick up a few things, it’s usually the most convenient option. For larger shops you probably want to go to SAS.