Mike -
The scotchbrite hand pads are cheap. I'm pretty sure I paid less than $1 each last time I stocked up. Look for a place that buys them by the large box and sells the individually out of the box (unless you can justify buying them by the box), rather than buying them retail packaged. Here they are for less than $1 each (for a box of 20):
http://www.amazon.com/3M-Scotch-Brit.../dp/B000LPN3WQ
I like the Purple/Maroon ones ("Type A Very Fine") for quick abrading action. I tried the brown (supposedly a little courser) but they seem to fall apart a bit too quick for my tastes (and not make the job go noticeably easier than with the purple/maroon ones). What's great about an abrasive like this is how well it works on a surface that's not totally smooth (it can "hide" surface irregularities and scratches, etc very well)
I usually just cut off whatever sized piece I need (usually a small fraction of the entire pad) using some scissors (I dedicate a free pair of harbor freight scissors to a hard life of abrasive cutting) and it seems to make just a single scotchbrite hand pads last pretty long. Often I'll just use little squares for little detailing jobs, maybe 1"x2" or so. Small pieces are good for getting into corners too. Don't need to always throw them out when done with one job, either. Can keep using until they fall apart.

Although a fresh one cuts faster than a loaded-up, broken down one so diminishing returns is applicable.
I have the three colors as well (brown maroon and green, pad and rolocs). I guess my mistake is getting them at the paint shop. Everything is more expensive there, I justify it since I am there for something else, but really pay in the end. Never made it to HD to try the other ones, but I will give them a try.