I'd spend ETH on a game with limited number of collectible units to make sure I could sell it later at a higher price. And this game must be funny.
Might be some money like $30 - $50 can be put into it. If it turn something big then it can be a calculated risk. Just read some steem topic, how somebody got lucky with a $2 purchase of this card. Actually he got some rare card and it is already trading for $1000