Do you know a Poll plug-in you’d recommend?
Something like Disqus, but for poll / survey to embed at the bottom of the page, would be great. Do you know of any free service like that?
I generally use Doodle if I quickly need to do a poll. Unfortunately it can’t be easily embedded on another site as far as I know.
You can however do it directly with Kirby if you don’t need registration/login/any complicated feature, for example by using a structure field for your options. When a visitor clicks on an option to vote, your template or controller would increment a value inside the matching structure entry.
I agree with @lukasbestle, if you don’t need anything overly complicated, you can easily achieve that in Kirby directly.
There are solutions out there on the web that you can integrate into your website, but the free options usually come either with ads or backlinks, or they collect lots of data, e.g http://www.poll-maker.com