Yes, you do need a minimum amount of reputation to vote. And for a good reason. We don't like cheaters. Hold on, I'm not referring to you. I'm referring to users who would otherwise quickly create accounts with the sole purpose to upvote their own content. And yes, this is a real issue. Reputation is part of the game, and any game will have cheats. So unfortunately, we do need to have minimal boundaries in place.
Seems a waste of time to bother signing up at this point, and sorry to the answer provider that didn't get my vote.
Yes, it's unfortunate that you went through the process of signing up, only to find you could not do what you signed up for. But welcome to the site though! Why not participate now you have an account anyway. The required amount of rep is easily gained, and we always like to have new users and great contributions.
As for the answer not getting an upvote, don't worry too much. Answers are not only of value to you. Good answers are of value to the community as a whole. And if the answer was really good, the user will still get a fair amount of reputation for it.
To be honest - for someone looking for a quick answer and trying to give a quick plus vote, this site is not very intuitive.
That might certainly be the case. The site does however provide a nice introduction to the basic concepts on the new About page. Check it out.
I know you said no need for a reply, but here you have one. Welcome to the site, and I hope you stay with us. And if you do ultimately gain the privileges, pay it forward. ;)