I have a thought for you to ponder.
This can be a knock on benefit to you from the project.
In the purchase of the cards you should be getting a kickback. If not you should be. 1 STARBIT in every thousand.
I would like you to think about creating a filter for cards listed with HIVE also. You get your kickback again. 0.01 HIVE for each 10 HIVE spent. Those are just numbers used. Not putting a value limit on your work.
i am aiming to build up a fund for the cards listed in HIVE also.
What the site takes is 1% of all transactions, which is something that is set in the contract before buying. NFTMart does the same. It can not be modified nor can you put more percentage, the rest goes to Rising Star Game.
I think the site generates about $8-10 a month, enough to keep it in service.
There is an option to view the filtered options with Hive, however it is rarely used. As I showed in the report I uploaded today, only 3 swap hive and a total of 400m starbits are spent on the page in a month.
Regarding what it doesn't let you buy, maybe you should select the account, it ended up buying the cheapest 300 without any problem.