That's kinda the whole point. If you could buy everything using iron from voting, they'd not make money because some people would rather just wait than spend money.
You can get some crates per month, or you can get I believe 1-2 ranks (Or at least on practice you can get up to gold).
The max iron a user can hold is I believe 2500. 2000 per month, if you claim it on the last day you have 14 days to get 50 votes for another 500 (Could be wrong, might not be 14 days).