I'm actually a bit late with this Etheremon related news. A few days ago, the team behind Etheremon released an update that has allowed people to trade (buy/ sell) mons, and lend mons out to others.
It's led to a market place with about 1000 mons for sale, ranging from 0.004 ETH, to in excess of 100 ETH for the original, #1 catch of most of the ''Legendary" monsters who can no longer be caught in the wild.
You can also "gift" a mon to another user via the trade function.
The discord group for Etheremon is optimistic about the future of the game, and the trading and renting functionality is implemented nicely. Initially, there was no way to easilly sort the market, but that seems to have been fixed today!
There's also a token that will work in game
The token is known as EMON, and is a standard ERC20 - with only 20 million tokens. The majority of these, (14 million) will be mined by players participating in the game. If you win a castle battle, you'll get an EMON token. You can use these tokens to build a new castle of your own later on down the track.
Along with all of these changes, there's been a slew of interface enhancements, which make the game easier on the eyes. (especially if you like Steemit's Night mode!)
Etheremon still has a lot of potential, and it is good to see the devs adding new features on a regular basis.