there is nothing aside from what you, the buyer, is willing to pay for it.since 2019 RV's have been artificialy high in cost because of demand and carry over from covid when all people did was spend to much money on rv's. I think I saw them starting to drop this year towards normal pricing but they are not there yet.
so when we bought ours we just looked around at quality vs cost, then you try your best to get a deal. if your not willing to pay the price some one with more money and less brains will.
even the private market can be a unreliable source. if some one bought a rv between say 2019 and 2025, then they paid a inflated price for that rv in most cases and hence when they list it they think it is worth more than it is. I watched truck camper prices rise from say 65K in 2018 for a nice canadian brand, to 98K in 2024 and this year is has dropped off to 83K .
basicly I found the quality that was aceptable to me, a floor plan that worked, and got them to drop the price a bit, and then throw in some extras untill I felt like I was making out OK.