How can I charge for my service without feeling bad?

I recently graduated from college and currently recruiting for full time jobs and Indie hacking. Back in college, I created a free e-commerce platform for college students to sell used products like furniture and clothes. However, someone commented that I should stop solving non-problems and that feedback stuck with me.

So each time, before I hop on a project I usually try to validate it as much as possible. I had a problem of forgetting the “tricks” and patterns for Leetcode problems I was practicing even after doing a question more than once. When I stumbled upon spaced repetition as a technique to boost memory retention, I thought I could use it for my technical interview prep. I built a browser extension that could store the questions and prompt me at intervals to review them.

I think it is a useful tool that can help people preparing for interviews to boost their memory retention. But I felt bad because the target market is usually students looking for internships or software engineers who are in between jobs. I therefore wanted to charge the minimum amount I could to get some money to get by too while looking for a job($4.99).

I launched it two days ago and I’ve got 6 users plus me so 7 users so far. I have never marketed before especially a paid service and I have been feeling some reservations when marketing the browser extension. I know a lot of folks here have marketed their products. How can charge without feeling bad?

P.S I am sure it is creating value and I think the amount is low enough (about two cups of coffee). I just need to get the voice outside my head and sell.