Well, if you do the cheap easy way as stated above, it'll be hard to stage the fronts. The reason is if you bridge the fronts (3.5" and 6.5" speakers) you could overpower the 3.5's and underpower the 6.5's. Or if you run the dash of the radio, it'll still be hard to dail everything in. Since 6ch. amps are hard to find and expensive, I'd either go with 3-2ch or 1-4ch w/1-2ch amps. With having each speaker on an amp, you'll be better off when tuning everything in.
That being said, I'd go something like a Kicker kx650.4, 4ch amp for the bigger speakers and the KX100.2, 2ch amp for the dash speakers. You should be in your price range.