Bolivia is very cheap when compared to Peru. Potosi doesn't have the tourist goods that you can find in La Pas, but if you are in need of anything else just visit the local market. People, like in most of the towns, gather around towards late afternoon and a festive atmosphere takes over. For those with strong stomachs and adventurous natures there is great street eating. My rule is if it doesn't have flies on it and/or you can see it being cooked it's good.
Of exceptional value are dynamite and explosives that are used in the mines. For about $1.50 you can blow up a small building if you are so inclined. We were amazed that these things were being sold with no questions asked.
When finished, wander around the main square. It is very pleasant for people watching.