listed is one thing.. but what do they actually sell for? - Also are we talking SKS or tapcoed sks?
Any way - Local markets fluctuate; i usually go by the country's market avg - $275 is on the high side for a tapco rifle. Unless you restore it to its orginal configuration; sell of the tapco stuff for usually 75% or less of whats it worth (that stuff is every where and not in high demand).
Usually it goes like this with regards to SKS in un-tapcoed condition:
Chinese Albanians can be had for 250-275
Unissued Yugos m59/66 - 350-375
Russian Refurbs 400+
Russian Non Refurbs 550+
Chinese COmmerical 300+
Albanian 400+
Romanian 400 +
Tapcoed anything without any original parts preserved/reserved - 250-275 on the high.
Now you may get lucky and get into a bidding war and hit 350.. but don't hold you breath.
Example: Two exact same rifles.. one tapcoed to mars.. another all original.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=438201641
Usually an unmolested example will go 100-150+ over that of a tapcoed rifle.
http://www.gunbroker.com/Auction/ViewItem.aspx?Item=450120998
Its the reason i always URGE caution when folks consider going down the tapco route . You will never get back what you have in it.. and if you loose the original parts you are hurting the rifles value.