How does the Magic the Gathering Card: "Daily Regimen" Work?

It's an enchant aura card my friend has. Basically he attaches it to a creature, and with each (1 colorless+ 1 plains) mana he uses he gets to put a +1/+1 token on that creature. So, with enuf mana, can he put say 7 of those tokens on that card in one turn? Do those tokens stay on that creature till the end of his turn? Seems like an op'd card seeing how it costs 1 mana to put the card into play.