Alright, because I'm a f*ck up, I didn't buy strap locks for my new Epi. Of course, it slipped and the headstock didn't quite break off, but it's hanging on by a thread. It splintered a little down the backside of the neck as well.

I'm just guessing that to get it fixed right will cost around $250-$300.

My question is, what kind of money will a broken Epiphone Les Paul Standard (lefty) get on eBay or something like that? Is it worth it to put it up and hope for around $200 or more?

Or would I be better off just taking it to someone to get it fixed?
I had this happen to me late last year, and I sent it off to an excellent luthier to get it fixed. The price he gave was no more than $350AUS if it didn't require graphite reinforcing, or $450AUS if it did. Thing is, though, it was only an Epi LP and only cost me about $900, so it wasn't worth getting it graphite reinforced, and he wasn't satisfied with the strength of the join when he did it, so he sent it back, and it's broken in my cupboard right now.

You have to strongly consider whether or not it's really worth paying that 250-300 bucks to get it fixed, when there's a strong possibility that it will neither feel or sound how it did before the break.

I can't say what it'd fetch on eBay, but I'd think that people'd mostly be paying for the hardware and pups that are in the guitar, so I wouldn't expect anything too great.
Its just a lesson in life. If you cant get it fixed cheap you arent going to get a whole lot on ebay for it. A new lefty is a little over 500 so whats a busted one worth.