you can see our recent sales in the sales rss at huntingmoon and also you can check out the weekly sales at dnjournal.com. tell.com sold for $400k at sedo last week. there is no average LLLL imho. every domain is different. there are some general pricing for all premiums ($300-$400) and non premium's but a non-premium can still fetch big bucks if it has other positive attributes. we recently sold udvd.com for $15000 and "u"/"v" or considered average letters.
Hmm, I have seen a bunch of CRAPPY lll's sell for 30-50 dollars. I have also seen some average ones sell for xxxx. They are really increasing in value though, IMO.
The starting price that I would say for an absolutely crappy LLLL.com is about $20 all the way up to a lot of money for something like PORN.com