If you're willing to, your best bet is to actually go to Craigslist and buy used. Rock Band and Guitar Hero games and peripherals swamp the gaming section there. You can probably walk off with everything for $60-80 bucks.
Regarding the best instruments, I'm going to agree with the other poster that the World Tour guitar is probably the best. Get two of those if possible. I've never heard any complaints about any of the mics, so I wouldn't worry too much about it. As far as the drum set goes, I don't know if the GH drum set works on Rock Band since GH uses five color inputs and RB only uses four. I would go for the Rock Band 2 drum set.








