1) Bulgarian citizenship can not be acquired on the base of small cash investment. There are strict provisions in the Bulgarian citizenship Act that require investment of serious amounts in the local economy, and specific terms to expire, before enabling applying.
3) For a foreigner who cannot provide local financial securities, it won’t be possible to obtain a loan from local bank to finance the required investment before applying for citizenship on investment basis.
4) Bulgarian citizenship on investment basis cannot be obtained in weeks. Actually the local legislation establishes precise long-term periods of residing in Bulgaria, before applying for citizenship on investment basis. If anybody offers to you to issue to you Bulgarian passport in several weeks time, it is most likely a scam.
5) In relation to the above last words, there is no private quick procedure to apply for, and to obtain Bulgarian citizenship, instead of the long governmental path via submitting application at the Ministry of Justice, and the Bulgarian consulates abroad.
Well, if you don’t know the local regulations, the assistance in advance (prior applying) of local experienced Bulgarian lawyer is recommendable for advising on the possible option and for respectively for organizing the paperwork that accompanies. It is always better to spend 50-100 Euros for proper legal advice, than to lose instead thousands given to online scammers.