Great questions. Sweet Maria's in Oakland is where I get the green beans, and they have a huge selection of quality beans, and they're all cheaper than roasted beans.
For $20 they will send you a popcorn maker (electric) and 2 lbs of beans. I can only do a few oz per batch with the electric popcorn machine but each batch is only 8.5 minutes.
Then you want to age the beans for a few days to release the CO2 and mellow out.
Basically it tastes great (to me), is cheaper, and I enjoy doing it myself. DO IT OUTSIDE if you don't have a coffee roaster, it produces a shitload of chaff.
First sourdough loaf of 2021