You can now Buy/Sell/Trade Steem Monster card packs on Steem-Engine. I just happen to be around and land the first ever pack trades for both Alpha and Beta packs :))))
I sold 2 Beta packs and bought 3 Alpha packs.
To buy packs you will need to deposit Steem onto Steem-Engine in the form of STEEMP.
To sell packs you can make your Steem-Engine account then go out to the Steem Monsters web page and select the convert option in the OPEN tab.
Here is a link: https://steem-engine.com
Best Regards,
Dreamryder007