I'm a complete noob at buying new or used guitars and equipment, and I'm wondering if this would be a good deal:

My friend is offering me his Epiphone SG G-400 Custom with a hard case for $175. He bought it used for around $300 three years ago. The low price is for a couple of reasons:

First, he dropped it once and it landed on the headstock, which broke it off. He had it repaired though, and it plays great. The damage is still visible on the back of the neck.

Second, the finish is a bit worn out in a few places. On the inside of the bottom "horn" the paint is a bit warped (he told me it was caused by sweat), and there's a small dent about 10mm by 2mm near the bottom of the guitar.

So what do you guys think? Should I buy it from him?
Personally, I'd give it a miss. Take a look around your local music shops and see if they have a new one, I don't think they're too expensive and then you can be happy in the knowledge that its never been broken...
If the repair had been carried out by a pro it should hold, but that wouldn't stop me being very cautious about it. Ive never heard about an instrument warping from sweat. Id tread carefully or offer a bit less if it was me.

Good luck
The instrument isn't warped, the finish is. The repair was done professionally. Thanks for the feedback!
That is cheap for the class of instrument you're getting - but repairs are never as good as it being structurally sound in the first place...

That said - if you're looking for the 3 pickup custom model you won't find it at even close to that good a price anywhere else - they're not exactly common - and they look pretty cool!
The only 6 words that can make you a better guitarist:

Learn theory
Practice better
Practice more