So last year for Christmas I got this guitar, a Gibson Les Paul Vintage Mahogany. Before that I had a low-end ESP LTD H-250 and I've been playing it and I realized that maybe I should get an ESP. How much do you think I could sell my Vintage Mahogany for? It's one year old and in great condition (one little dent on the body, below the knobs, not very noticeable because it is hidden when you play sitting down).

I'm not positive if I want to sell it, but it's just an idea.

(And yes, I also realized it was overpriced before you ask. But it was also $100 less than how much it is now)
Check eBay and see what they go for on there. Then take a little bit off of that maybe, or throw in some extra stuff.