i wouldn't suggest going to bulgaria after 10th sept bcs most of the parties, boats and trips might be over, if you book now you will get a huge discount anyway, the currency is BGN, around 2,45 BGN=£1, deffo do the jeep safary trip, it doesnt matter what agency you go there with, they all offer pretty much the same things, the best period to go is maybe the last week of august, the catamaran trip is pretty cool too, i wouldnt suggest the party boat trip tho, idk it might just not be my type of thing, i didnt like it much.. and dont forget to talk to your rep if you need help/have problems/whatever, they will 11/10 help you or try to do something for you, i hope you have nice time there