I'm willing to spend up to $70, and according to every PSU calculator I've been on only need a max of like 200W for my system. I would like it to be modular which is why I am considering the first one.
I checked several technical references. You'll be fine with the Enermax Liberty ECO 400 watt power supply. Enermax usually does very well in technical reviews. The Liberty models did a little better than some the other models.