I have been to Bulgaria 3 times - the first time was about 10 years ago and it was really, really cheap. you could get 250 lev to the pound. then i went again 3 years later and the currency had increased 10 fold ie you could get 2500 lev to the pound. It used to be really 'old time' - unspoilt, there but john is right - it is catching up, still, it's cheaper than Turkey. You can get alot of rip off stuff - fake designer clothing, trainers etc. but you can tell they're rip off. Bulgaria is mainly mafia run - protection rackets and stuff. It used to be dodgy for tourists because of the gypsies there but they have all been cleared out of the resorts now. The only thing to be careful of is exchanging money there. NEVER do it outside of your hotel, you could get ripped off and they don't care and will even get the heavy mob out to an 80+ year old - as happened when i was there (not to me i might add). Also you are not supposed to take any of their currency out of the country.
Apart from that it's well worth going but this year prices are rocketing as they will be joining the EEC next year and won't be able to continue with their rip off stuff so much- y'know - conforming to European legislation or whatever....
Try it - see what you think - it may all change in the next few years. My dad goes EVERY year and loves it.