That's ebay for you. I know the person who had the LB rear sight that went for $125 - I had my fingers crossed for him, but I also get worried when the parts start going out of my price range (which is not high). I'm glad that I picked mine up for $75! I may have also located an LB Mk.1 cocking piece that I can afford - the joys of the internet lol.
My visit to the gunsmith turned out profitably - picked up an unserialed LB magazine with the solid underside and a nice plum tint to the bluing - for $30. He also had a selection of bands and some other magazines (mostly Indian service with several serial numbers stamped on them, but he was going to be selling them for $15 each - not bad for my neck of the woods lol).