Hi!

1. Voting on Steem in general does reduce your voting power - this also applies to votes made via Steemvoter. But don't worry, your voting power recharges back over time, and you have full control of how much of it you want to spend per vote by setting Voting Power (Weight) parameter when following another account or a guild via Steemvoter.

2. Steemvoter is free to use for the duration of the beta. After the beta is over, the will always be a freemium version of Steemvoter where you can use the product in return for us using an equivalent of one full vote per day from your account.

3. No! You can simply pick some accounts you like to always upvote and create a Stream, you will get curation rewards for each vote you make. Or you can create your own curation guild and group authors you like by a certain subject.