Just did a quick search for you. Some of these aren't as recent as I would have liked but this should at least give you some hope..it's not as if this data is 10 years old after all. I'm sure if you did some more digging you would find some great prices out there in the last year or so too. You really have to cast a wide net when it comes to buying SW, think about going to local shows, checking all the various auction sites out there, local classifieds and remember to check ebay constantly (especially for funky listings or cheap BIN's).
Vader: http://www.ebay.com/itm/STAR-WARS-1983-PALITOY-TRILOGO-DARTH-VADER-/142204874303?hash=item211c122e3f%3Ag%3AkJ0AAOSwnHZYRdDa&nma=true&si=CA4zThymk5K7CA2KNHNWWBwT43k%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
Luke: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=629610
Han: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=606370
Chewie: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=613668 (Autographed so..meh but it was a nice looking figure)
Leia: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=606457 (Splits..so not really C8 but fair price for condition)
Jawa: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=628499
Tusken: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=606455
Stormtrooper: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=573388
Ben: http://www.vectis.co.uk/Page/ViewLot.aspx?LotId=588875
I hate to say it but I rarely see a great priced Trilogo on FB, even in my own group. I try my best to give realistic valuations but I can't dictate what people ask for their items. Collectors have become too interested in profit margins and making money to let anything go for a decent price (well all except Iain perhaps!) so my advice is just ignore the asking prices and do the leg work yourself. Vectis get such a large volume of items through that there are bargains to be had and as I said ebay is a good place to source figures from too.