$700 and $1500 are the going rates for most general purpose implements. Dealers pay the 700 and get the 1500. So to answer your question it depends. One on one sales are usually the best for the buyer. However if you are a potential buyer and need something the dealer is usually the place to get it.
Gotta consider they have to find the stuff, sometimes takes a lot of looking, a lot of auctions and all, sometimes fix things broken, meaning they have to find, acquire and pay for the parts and labor, have to have OTR equipment to haul it home, have to pay business overhead and on and on.
I don't begrudge them and have bought and sold a lot through the local after market dealers.
On things like balers, we have a lot of Mexico competition here so they are a little pricy. However, looking at some of the prices folks up in the Northern tier of states some folks are asking, things here are cheap. Condition and popularity usually weigh big in the price.
I guess my answer would be what the buyer is willing to pay and what the seller is willing to take. Nothing like a good "haggling" when you are in the buying mood.