Hypercomments used to have a free plan suitable for small blogs like mine. Since May, 2018 there's no free tarif plans anymore.
I searched for alternatives to Hypercomments. First I switched to another service called Vuukle. I've installed it with no issues. However, published comments used to disappear after I reloaded the page, while comments counter was showing the correct number. Weird.
Then I've tried IntenseDebate. They didn't have the same problems, but the design was outdated. Also, you have to register in Intensedebate system to leave a comment, you can't post as a guest or login with Facebook/Google etc.
Finally, I tried Widgetpack and was happy. It integrates easily, allows to post as a guest or log in with social networks. I don't know how long will they last as a free service, but this will do for the time being.
Anyway, I felt I needed to update my blog, haven't touched it for a long time.