Ask HN: Resources for user feedback on a website

I am about to launch a website which I have built as an MVP and I want to be able to collect/encourage feedback from users -> does anyone know good (ideally free/with a free option) resources to facilitate this? I am thinking user forum/issue trackers/on-page widgets to collect feedback and report bugs etc etc.

I don't want to spend lots of money but I do want to a) validate my idea and b) get feedback to orientate development going forward.