Survey software collects structured answers from people and puts them somewhere you can analyse them. The commercial market prices that by response volume, which is where the arithmetic starts to matter. SurveyMonkey's Team Advantage plan is £20 per user per month billed annually, with 50,000 responses a year and £0.15 for each response past it. Typeform's Basic plan is US$28 a month for 100 responses a month. Qualtrics quotes rather than publishes. Google Forms is free, and for a simple feedback form it's frequently the right answer.
LimeSurvey is the open-source alternative in this category, and it's a serious one. Written in PHP, developed since 2003 and looked after by LimeSurvey GmbH in Hamburg, it's widely used by universities and research groups for the kind of questionnaire hosted tools handle badly: conditional branching across dozens of questions, quotas, randomised blocks, several languages inside one instrument, and export straight into SPSS or R. Version 7 is the current line and needs PHP 8.1.29 or newer, with the 6.x line still available alongside it.
People rarely self-host it purely over the licence fee. It's usually response limits that don't exist and question logic no hosted tool will sell you, with data residency close behind.