"Hi, we are not going to pay you, or not very much, but please be at the same level as senior that are already working for us"
I had interns back in the day I had an office (and not working from home) and I always made them work on basic tasks under my supervision. Once I had one woman who was very good, and she worked on a website that ended in production, but most of the time the purpose was to work on internal projects that can be used even if not perfectly polished. You know, stuff you always say you're going to do some day, but you don't.
The advantages were on both sides. They learned real life cases, under my supervision, and I had the tools I didn't.
Disclaimer : I'm French so maybe my example is not relevant.