Best way is creating/using them in different browsers in your laptop. That's what I'm doing and also manage a few subreddits with them.
No need for expensive tools for only 3 accounts, neither different IP's. Just create them in separate days.
As
@karupoiss said, upvotes might not be counted from all the accounts being on the same IP, but anyways 1-2 more upvotes doesn't makes a big difference.
You still need to be careful if you're going to use them to market some offers, having one account reported might transfer the flag to your other accounts. For personal use I wouldn't worry about that though.