I will have a 275/35/18 Toyo Proxy 4 and a 275/35/18 Michelin Pilot in a couple weeks. The Toyo is like new but the Michelin is about 65-70% and has a little dry rot. I'd let both go for $100.
I'll have my 245/40 Toyos for sale in January after I pick up my new 10's for the front of my car too. I'd sell those for $250, they are perfect. So $350 for all four if you could wait.