I love my firewire mixer for its convenience. The cheapest I've seen is $300 for either an Alesis or a Phonic. The real difference between the two is Alesis sends streams post fader which includes EQ and fader. Phonic sends streams post gain which does not include EQ or fader. I prefer phonic's method because I want unaltered audio going to the computer. Set the gain, let it go to the computer during tracking and make all your adjustments there.
Hope this helps.