I'm going to agree with Marty, in the fact that 5% upfront fees does seem high. However, I they are the only broker you actually feel you can trust, then I guess a 5% sales fee is better than no sales fee, and then they take your money and you never hear from them again.
However, I thought that Vanguard is starting to grow in to more countries, and especially the EU. So I'd check to see if they offer anything.
Since you have slim pickings for brokerage, maybe you don't invest in stocks, and do something a bit different. Invest in companies or real estate in your local town? I know nothing about the laws or economy of Bulgaria, but maybe go talk to banks or investment centers to see if you can start loaning out money at a higher return than just a savings account. I know in USA, you have to be an accredited investor (net worth of like 500,000 or something like that), except luckily p2p lending allow a way around that, in order to loan money out like that but maybe your laws are more relaxed. Are there p2p lending businesses in Bulgaria? Or to at least invest in?
I'd say that if you feel there are no reputable brokerage houses to invest in, or that you feel comfortable in, I'd go with some of the examples I said, or maybe some other people will think of some other examples. Just trying to get your mind working.