In before all of you start the usual 'he is best player in the world already' blah, blah, blah...
Yeah, but he is 17! SEVENTEEN
No such deals can ever be given to a 17 year old.
Ask yourself how much he will be getting by 23, by 26, by 29, and so on.
Messi wasn't getting that amount (relatively to the time) compared to market, and wage structure of the team, neither at 19, nor at 22, nor at 25.
Still, at some point, he got a 100m gross per season contract that bankrupted the club, together with other ridiculous contracts.