When I bought my first 4x5 Anniversary Speed through Ebay, some 5 or 6 years ago, there were a half dozen or so that sold the same day, virtually indistinguishable from one another by description. They varied in sales price from $75 to $450. The passion engendered in a bidding war sometimes makes people a bit crazy. Patience and shopping/prospecting locally seems to be the more fruitful path, at least around a city like Boston.
I purchased a 1955 Speed Graphic with the 135 mm standard lens and the Fresnel ground glass back one year ago for $209 shipped.
It is in excellent condition, all working and the shutters are accurate.
I use it with the RH/8 back and medium format lenses.
After a lifetime using slr, I find it difficult to operate especially hand held, I usually mess up some shots per roll by incorrectly sequencing shutter dark slide and film winder
here it is with a Computar 105 ~150 mm variable focal lens which is adapted via a home machined lens board
two years ago I bought my speed graphic from eBay and from European seller for 270 Euros (today's rate is USD 355). Fine and working condition with optar 135mm and kalart RF.
Perhaps not the cheapest, but as I got cheaper shipping costs (flatrate shipping from italy to finland) and needed no customs and taxes that way, it was good deal when comparing buying from US.
So pricing of speeds in Europe aren't always such high.