I pay $20 for 2 gallons, 1 of a and 1 of b. Its called Highgro and works very well. It is mixed locally (not that locally lol) but bottled with a few different names.
I'm personally a big fan of the House & Garden (http://www.house-garden.us/) range for additives, but they too are quite expensive!
I don't use the shooting powder though, I use GH KoolBloom powder in place of that, much cheaper and works a charm! Also, in my experience you can use pretty much any brand of base nutrients in place of the House & Garden stuff if you want something slightly cheaper.
WOW greenphoenix that is a sweet ass harvest, look at the size of those babies!!! thanks for all the comments you guys. in the end I went for AN sensi grow and bloom, got some liquid silicon, superthrive (which is amazing!!) some AN carboload for the rootbastic from atami and finally cannazyme. everythin seems to be good at the mo. if there is anything else I could be doing please please say as im a newbie and would appreciate it! budie