Do you have any rim/tire dealers in your area? even a garage maybe? Ask them if they want to buy them. If not, ask if you can put them in their shop and if they sell, you will share a certain percentage with them. (consignment) Or if you could put an ad in their store. Go into the Auto parts stores and ask the people that work there...if they aren't interested, they may know someone who is.
Also, where I live, most of the small "moms and pops" convenience stores have bulletin boards you can advertise on.
If your're only getting offered 400, I would even check with a pawn shop..they may give more..Pawn shops are always my last choice, but you may get more than 400 and get rid of them.
I know alot of gear heads, so I usually don't have a problem moving anything to do with transportation, especially aftermarket add-ons.
Check with any local car shows that might come in the area.....Also, google Car Clubs in your area. People who pay good money to get their car, and maintain their car the way they want are willing to pay a fair price.
In my past experiences, teenagers are usually the ones that will throw low ball figures at me, mostly cause their funds are limited.
Good luck