I have the 4s but it is in 02 boxed and good condition white . 170
I have a black 4s that I bought as unlocked but I've never tried it with another sim so can't say for certain. It's boxed, in good condition and works on orange / EE, as that's what I'm on. Make me an offer because I don't know how much it's worth? Cheers!
If you send me the IMEI number (pm not on open forum) I'll check it for you and see if it's unlocked.