My g/f's brother draws Superman or Justice League (or something.. He's done The Mask and other stuff). He's got all these old original drawings... and though not much a fan myself I thought it'd be great if he sold them, y'know, online.

Do you guys think that's a good idea? (He's a bit ambivalent towards the idea.)

Also, if it is a good idea, what (ballpark) price should they sell for?