Instead of feeling bad, pitch in money when you can, but even better pick one you could contribute to and contact the maintainers asking how you can help. Then

Instead of feeling bad, pitch in money when you can, but even better pick one you could contribute to and contact the maintainers asking how you can help. Then you're giving back and improving the software along the way, I don't think you'll feel bad when you're contributing time to an open source project. The tech world runs on open source, use it and give back when you can.