Not entirely , it costs you voting power , but that's something you receive for free.
And get's reloaded all the time. check it on https://steemd.com/@blockgators
Powering UP increases your vests and therefore your voting power , so every vote (including votes for yourself) are more worth than.
This is your only possible input/cost on upvotes.
Steem power can be checked in the open wallet on every account.
Seems you're a bigger steem believer than @suppoman , :-))