Yup, cheap, cast friendly and very usable.
Assuming you're in the US, then the permit isn't for usage, but rather ownership. The "Tax Stamp" for the suppressor is $200, and requires a background check before approval (seem to be taking about 8 months at the moment). It's a PITA, and probably unconstitutional, but it's the law. Some states don't allow private ownership, most do.
Once you own the suppressor, there is no maintenance fee or anything like that, it's just a once and done deal with the tax stamp.