Your comments

I've fixed that double trouble price.  THere were some "Royal" variant sales in with the base ones which inflated the price.  

Regarding the other marketplaces, we would like to add other sites too.  We are actively working with a few new ones for high end trading and sports cards.  I will reach out to Mercari and see if they can provide us the information we need to add their sales as well.

How can users tell which sets those came out with?  Unfortunately our system requires each card to be linked to a set.  The year looks to be a unique identifier, but multiple sets will come out per year.  Will the energy cards for 2021 all be unique regardless of the set?

We don't have that feature at this point.  I think it 's a good idea though.

We used to have this feature but closed it down years ago.  

https://blog.pricecharting.com/2013/02/closing-dvd-blu-ray-pricing-site.html

In our experience, most DVD's aren't worth very much and very few are worth a bunch of money.  There wasn't much demand for a price guide when we had it on the site.  Things might have changed over the last 10 years but I still buy most of my DVD's for $3 or so and hardly ever see ones worth more than $10 so I don't think this is a market we will be jumping into soon.

Yes that would be technically possible.  I'll see how popular this feature request is before implementing it.

Sorry for this problem.  If you enter a blank space character instead of leaving it blank does that solve the problem?  This will help me troubleshoot the issue and find a solution.