Price range is 0-$150 ish, really don't want to spend much thought. Portability is a plus, but it has to be able to play while being charged. These are going with my Soundmagic hp150 (happy with the purchase btw), which are only 32 ohms, so I don't need a super strong amp. Any recommendations?

Personally, for 32ohm headphones, I don't think you need an amp at all. That said, check out FiiO E6, small, VERY lightweight, can be used while charging and can drive headphones at least up to 80ohms. (highest I've tried with it. Didn't have problems at all, not even max volume needed.) Best part - can be bought online for under 30€. (At least back when I bought it.)

Also there are of course other FiiO products (for more money), but can't comment on them, because I don't own any others (except for E02i, with which I'm also happy. If you use an iDevice, maybe check that out too?)

I use a Cayin C5 with my HP100 and it pairs very well with it.