what?!? $25-50 per "minute"? Is that what I should be charging?

Why charge by the minute? I just finished two tracks for an indie game at $25 a track.

I can't tell you what to charge but I can say that $25 for a full track is a very low rate. Consider raising it. I find charging per minute helps quantify the work and effort going into a project and makes the cost directly proportional. For example a short iPhone OST of only two five minute tracks will be completed much faster than a PC game OST of ten five minute tracks.

now i feel like i sold myself short But this is only my second project, i just started doing game music and had no experience before.

Don't stress out too much! You're learning - it's okay!

What are most indie game devs willing to pay for game music? It's just really hard for me to see an indie developer paying $300 for their game. I know that a lot of indie devs don't have a huge budget

It really varies but I've had plenty of indie games pay $300 for the audio in their game. Heck, I've had several indie developers pay in the thousands for their audio and it's becoming more common - so you just never know. A few tips:

1) When negotiating always aim a bit higher than what you'd consider your bottom or "fair" price. This way if the client makes a counter offer you can wiggle the numbers some but still make a wage at (or close to) the amount you were hoping to make.

2) With higher budgets come higher expectations. For a client only paying $200 for the music (and I've had my fair share of those projects) they'll most likely have lowered expectations. But if you have a project that is paying in the thousands then expect some high standards and be able to meet them. It can be a very healthy, fun challenge. Raise the bar on yourself. Push yourself beyond what you think is possible.

3) Always consider revisions when negotiating a contract. Personally I only allow for three revisions (per track) included in the initial cost. More revisions cost more money. I do this because I've had clients that have wanted to iterate just to iterate. This can be very dangerous because it starts eating up a great deal more time than you originally budgeted for, can cause frustration and in the end - not really lead to amazing results. After all, iteration is good - but iteration just because is hardly ever good.

4) Value you work. Every once in a while raise your rates. I do it annually - but I'm also more than willing to make an exception for a repeat client. So be flexible with it - but value your work and hopefully the client will as well.

Keep your head up man. I'm just thankful that you're already charging on your second job. I've seen FAR too many guys work 10-20 jobs for free in the vain hope of landing a "real" job that will be the next big thing. That hardly ever happens.

Going to second Nate's points - I'm only a starter/intermediate level but I've already decided that the "free work" route is just unsustainable - you have to know that what you're doing is valuable and worth paying for. The problem with doing free work is that it's likely to be a zero-budget project, which also adds the potential problem of the clients losing interest and not pushing the game out in the end, resulting in a load of wasted time on your part.

I'm starting to realise the importance of contracts as well - there are a whole host of negotiable points that you wouldn't necessarily have thought of before, like the clients rights (full copyright/single-use/per-platform, etc) and the costs of rewrites, additional work, remixes, etc. It can add up to a substantial amount of extra time, which again shouldn't go unpaid for.

I think overall, just remember to value your work - if you don't believe that the service you provide is worth the money then there's no way your client will!