If you sell to a shop you're going to lose money the same way you do trading in anything else, since the shop has to take a cut to sell it at a profit.

I'd sell on Reverb.com. Make sure to take it to your shipper of choice (UPS, FedEx) and have their store pack the item because this will place the burden of damage during shipping on them. They'll do it correctly with the proper box and foam sheets to keep it safe. If you pack it yourself, it's on you if it breaks. Some idiot tried to ship me a guitar on Reverb by packing it in a soft guitar gig bag, inside a box stuffed with a half-assed combination of packing peanuts, bubble wrap, and bunched up paper grocery bags. The thing cracked at the neck joint and that guy was out $1200 because shipping insurance doesn't cover damage from a shitty packing job.