throw em on kijiji and find out
they are worth what someone will pay ya
heres my thought process since you asked; people look to buy used tires because they are just that; used and usually sold at discount. if you are asking a similar price to new tires/rims, why wouldn't i just buy them brand new?
lastly, if you ended up paying 400$ more for new tires/rims why wouldn't someone else just do the same? the marginal benefit of going new over used with that sort of investment is worth it. (say you're asking 1500) then you're obviously not shopping for a 'deal' so why buy used?
in short? 1500$ is to much; might as well buy new; 1000$ you will probalby get some bites. 800$ and they'll be gone tomorrow night.
so its your call