Is "POP Marketing" (in the thread title) the name of the sales agency or a reference to the general technique (Point of Purchase marketing)? POP as a general technique means the agent does some extra things to promote the sale directly with potential buyers, maybe displays it at a show or hands out flyers or whatever. Are they promising to do anything like that? I've not heard of a sales agency named Pop Marketing, so right away I'd be suspicious.
Next question is what makes you think they can get a higher price than you are asking? Obviously your RV is less attractive to buyers if the price is higher, so where is the advantage to you? What will they do to make it seem more valuable to buyers? Will they advertise more widely? Show it on their own sales lot?
Last question is are they asking for an exclusive sales contract, i.e. only they can sell it and at a price they set? How do they handle lower bids from a buyer? Do you still get your price? And a dozen other "what-if" questions about the actual transaction and their cut of the sale price.
