Such stores only give you about 2/3rds ~ 3/4ths of your used console's actual worth though, so if the OP wants to sell it online or something it would be more than that, around the price of a new O2DS pretty much if he has the box and everything...I sold a pink small O3DS in perfect condition (repaired with ntrboot), box and all accessories two months ago for 70 € to Cex (which generally pay above average)
How much does a used O3DS usually usually go for? I'd say sell for a bit less than that so they can get rid of it quickly (but that's up to OP). The warranty may not be honored if it's purchased new. Some companies only honor warranties if you buy directly from an authorized seller with proof of purchase. I don't know if it's like that with consoles but sometimes it's like that with musical instruments and other kinds of electronics.I'd say 70-75 pounds if it's in great condition or even 85-90 if you got the box and warranty... Also, if it has CFW, you can't sell it (it's illegal), so uninstall it first before selling it.
With consoles you just need the receipt and you get to use the warranty whenever you need it until it expires.How much does a used O3DS usually usually go for? I'd say sell for a bit less than that so they can get rid of it quickly (but that's up to OP). The warranty may not be honored if it's purchased new. Some companies only honor warranties if you buy directly from an authorized seller with proof of purchase. I don't know if it's like that with consoles but sometimes it's like that with musical instruments and other kinds of electronics.