Calvin - Smallish one under the Rila Hotel where you can get most of tourist needs. A larger supermarket, with better prices and choice, is the Billa in Samokov Town, on your left as you approach Samokov from Boro. There's a bus that goes right outside Billa from the Ela Hotel.
Calvin - live in Kent but have been going for some 20 years, so know my way round a bit
By bus, allow 30 mins or so and costs 1/2 lev. Taxi around 15 lev down to Samokov and 20 lev back - always costs more back to Boro BUT agree price before getting in taxi. They may agree to wait if you are just going to supermarket.
Roughly in front on them on the right is a small convenience store rather like a Spar but much smaller and less well stocked. If I was self-catering I wouldn't shop there for veggies. Fruit was ok.
Beleive it or not, there is a supermarket named tesco in Boro .......next to chilli's bar.
Maybe we might see aldi's or lidil's in Boro next season
Fiona
You usually have to book a day or so in advance either through your rep, which is the most expensive or you could get your ski instructor to haggle for you. You can also walk round and speak to them direct. If you do a search on here, there's a bit more info.