How many different types of guns do you have and what do you plan to do to them? Answer that and it will help guide your tool selection process. If you only work on S&W revolvers and only then to clean then you won't need much. If you have different beands of revolvers, semi auto pistols, bolt rifles, semi rifles, shotguns, etc and you want to do full disassembly including removing threaded in barrel then you will need much more.
Brownell's is the best place to buy, but careful shopping can get you a better price on some things elsewhere. As stated, do not buy cheap. A poorly fitting screwdriver blade will chew up a screw. A blade that breaks will damage the receiver.