http://www.ebay.com/itm/Sensation-Comics-1-CGC-5-5-Golden-Age-Key-Comic-1st-Wonder-Woman-Cover-L-K-/291408166398?ssPageName=ADME:SS:SS:US:1120
Here's one discuss . . .
It seems the WW key books are a bit all over the place in terms of pricing, so it's really hard to say where FMV is right now. GPA certainly doesn't have much in the way of sales of Sen1 in the past 12 months other than a 5.0 with LT-Tan pages and Tape on Cover (and a fairly large piece at that) going for $16,133. So a much nicer looking 5.5 with OW pages and a real clean FC certainly should be valued much higher than that.
Also, just looking at AS8, recent 5.5 sold for $44,813 and a 5.0 sold for $28,680. The 5.0 was sold at the last Heritage auction where they listed the start time incorrectly (CST vs EST), so it was thought to have sold about $10k-$12k below market value due to the fact that the listing ended before most folks thought the auction was even going to start.
If Overstreet is any help at all, it values a Sen1 at about 65% or so of a comparable AS8 given same grade. Probably a stretch, but that would place a Sen1 5.5 somewhere between $19k (if you assume the last AS8 Heritage auction is FMV, which many argue it was way too low) to about $29k. Just based on recent AS8 sales.
So my clearly amateur guess for a nice looking Sen1 5.5 with OW pages is about $25k give or take. It makes me think this particular ebay listing isn't too far off-base. Now, on the other hand, the conserved Sen1 1.0 on ebay with the $45k asking price is absurd.