It really depends on the description. The SE/30 auction description page is not very good and the seller is only accepting local pickup, hence it hasn't received any bids. If a machine is complete, photographed working, well described and the seller is willing to post, it will generally sell quite well at the moment. I sold a spare, stock Mac Plus earlier this year and I got £35 for it - I offered postage but the guy who bought it lived near me and came round to pick it up!
Of course, the really hot auctions are the ones for Colour Classics- they're making loads at the moment. I actually had the chance of four free CCs about 5 years ago and I only took one - really regret that now!
I'm certainly hanging onto the one I did get!
Though then again there's an SE/30 just underneath that Classic in the "Vintage Mac" section and it's only at 99p at the moment, and SE/30s are the most sought after Compact aren't they?