Hi and welcome to Steemit! I've been on here for about 3 weeks or so and I'll try to answer some of your questions, although the best way to learn is go into the #steemit category and search through the articles (there's some controversy on the way the voting system works right now and lots of members are sharing ideas and suggestions).

High rep members (whales who have a lot of Steem Power) and all members in general do not lose rep points for upvoting. You can only lose reputation if people downvote your post aka mark it as abusive or not valuable. Your reputation is based on lots of factors but basically shows how popular your posts are.

There is no cost to upvoting except that if you vote more than 20-30 times a day, each of your votes will be worth less. So say you have 100% of your votes and you vote one 4 posts. That means your vote is distributed 4 times and 25% of what your vote is worth (which depends on your steem power amount) will go to each article/comment. If you vote 10 times, then obviously each post will receive 10%, etc. (this might need a little more research, there are posts that get into the trchincal details of distribution that are a bit beyond my scope of understanding).

This follows the logic that if big whales upvote a post, their vote will be worth more and the author as well as anyone else who is up-voting the post will get a bigger amount of steem dollars and steem power. It seems like most whales are upvoting content that is probably already in their feed, and many users are encouraging them to spread their reading wings and try to find new authors and new posts to upvote.

So it has nothing to do with rep, but probably just has to do with humans not having enough time to upvote lots of new posts or keeping to the authors they already have a developed relationship with.

Just keep posting great content, engage and comment and upvote other people's posts and hopefully a whale will notice you and like some of your work. In the meantime, as you learn more about steemit, yoi can share yoir thoughts on how to improve the system so there is a more equal distribution of power. :)