advice for selling a boat

So I have a 2002 vlx that im looking to either sell or trade in. Just thinking its time to upgrade to either a 2010 or 2011. I'm the original owner, has 500 hours, and every option that came with the boat that year except for a wedge and perfect pass (didn't realize what a difference those things would make back then)

Does anyone have an idea about what it would would roughly be worth? I looked in boat trader and I see a 10k swing between20-30k. Just had it serviced at paradise and they said it was in great shape.

Any advice or where to find this info would be great.