Technically, CheckOutMyCards.com will not change for a couple months. COMC.com will simply never have the feature that CheckOutMyCards.com had where we gave out Beckett prices to the public for free.
The original seller of an item will always be able to see the book value from the Manage Inventory screen. We consider this a critical part of being able to efficiently set asking prices.
One of the things that the book value did as we were growing is that it forced sellers to set fair asking prices. Now that we have an average of 3 instances of any given card, the market is doing that for us. Sellers are setting asking prices relative to each other.
Ultimately, this change was an inevitable consequence of being a successful site. We could only publicly show book value as long as we didn't have enough coverage or popularity that it might discourage people from getting Beckett subscriptions.
Now that we have nearly 1 in 3 Beckett values and we are very popular, there are a lot of people publicly encouraging others to cancel their Beckett subscriptions and just rely on CheckOutMyCards.com. If you think about it, it only makes sense for Beckett to continue licensing data to us if we pay them more than they would lose from the people that don't get Beckett subscriptions.
Our plan to make sure that our business relationship with Beckett makes sense for both sides is to phase out any publicly visible book prices and to offer an upgrade option for buyers that want to see the Beckett values. People that like the feature of seeing the BV next to the price can still get it. At first we will give basically an "all access" pass for $10/month, but we may add more granular options (e.g. 1 Player or 1 Set) if we get enough demand.
All of that said, we do see some benefits from this for both buyers and sellers. The site becomes significantly cleaner and easier to read for buyers. They don't have nearly as many number jumping out at them when they simply want to buy a card. Also sellers won't need to feel so compelled to charge something relative to book value. For example sometimes people think a card won't sell if they ask more than half book. Well, that may be the case if the buyer had to spend an hour digging through your dollar box or scanning your show case to find your card, but online they only had to spend a few seconds typing in their search. That time savings is worth a lot, and people are more than happy to pay a little more if they can save a bunch of time.
In the end, this should result in market prices being driven by the market and not by book prices.