in bulgaria all gear is really cheap. not sure on the ski boots front but if you wanted to buy the full snowboarding gear, board, boots, bindings it would cost bout £200 max. best thing to do is ask your instructor to take you to the best shop in the village and they can sometime ssort you out with a discount
There are some good discounts to be had in this country at the moment - so shop around here a bit first - most importantly make sure you go to someone who knows how to fit the boots for you.