Mana isn't a token but rather a property of Koin. It recharges automatically like a battery. That means you can do as many transactions as you want for free and then just need to wait for it to recharge. The fee is essentially time. It's similar in a lot of ways to the RC that you used based on your powered up Hive to post your comment for free. The biggest difference is probably that you don't need to stake or "power up" Koin ahead of time in order to use Mana, but there are other differences as well.
On the claiming site the Koinos group is paying for the Mana for all claims. After you claim Koin you'll have your own Mana to use.
RE: Koinos x Hive