Those books were really expensive back when they came out.
I haven't noticed a lot of interest in these though as most stories have been reprinted again by IDW. These original trades were of better quality though, particularly the UK reprints. I think you could ask $40 for the UK trades and the hardcover US trades and around $30 for the softcover US ones.
The Best of UK/Simon Furman signed book should be worth a bit more. I think you could ask for a high ammount and then drop it if there's no interest?
The Wreckers book is cheap at Target if people can still find it. I don't think you'd get more than $20 for it at this stage. Maybe hang on to that until it goes out of print. There's likely to always be demand for that story from fans.