Mark Salo wrote:
We get one free vote!
Otherwise it's only a dollar per vote.

The contest appears to be run by the Andrew McDonough B+ Foundation (bepositive.org). It's a 501(c) organization that focuses its core mission on fighting against pediatric cancer and has a 97.64% program expense ratio as reported on Charity Navigator.

Rating Information
Good
This charity's score is 75%, earning it a Three-Star rating (out of four). If this organization aligns with your passions and values, you can give with confidence.

This overall score is calculated from multiple beacon scores, weighted as follows: 90% Accountability & Finance, 10% Culture & Community.

Ultimately whether or not anyone decide to pay for extra votes is up to them, but it's not a shady website contest.