Unless they are semi pro or pro models , or a sought after classic model then you aren't going to get much for them at all.
For example..
Canon EOS500n - typical consumer camera of late 90's - £15-20 for body, £25-30 with lens on ebay.
I just bought a EOS30 with battery grip for £50 - probably cost around £450 in early 00s !
By the time you photograph your kit, place the advert, sell, package and despatch its hardly worth the effort these days.