Voting bots are super useful, they help you raise your internal steem power as well while at worst coming close to breaking even on SBD spent and rewarded. Dozens on steemit have spoken balances over a thousand and never bought a single steem. I myself have raised my steem power over 100 steem over the last several weeks from using upvote bots/accounts.

Also to find even more steem tools check out http://www.steemtools.com