A-Wing will be over £200 (got mine for around £200 but thats the cheapest i've seen it).
Skiff will most likely be £300-£350
Sandcrawlers are going for £350, but if you want a nice minty one with unapplied stickers then its going to be quite a bit more.
Kenner Death Star's have been going for over £200 for ones with inserts and all in good condition.
If youre living in the UK though - you'll probably have to buy from the states - so expect to pay huge postage. They dont seem to come up for sale in the UK.
I've not been about long, so some of the others might have better ideas.
2 have gone on ebay in the last couple of days one for around £360 (rc not working) and the other £468 (very nice condition) - I missed out on it by about £5 lol - it made me do a sad face.