Use regular laser printer. Add a thermal printer if you start shipping, say, 100+ everyday.
Pod bags: Amazon itself. Corrugated boxes, bubble wrap: check on indiamart > contact > easy.
If you don’t sale through FBA you don’t have a chance of surviving on Amazon. Amazon has made sure of that.
FBA = Prime
SKU handling has nothing to do with becoming an FBA or prime seller. The better question you need to ask is how to do Wearhouse or inventory management. Back in the days i used ucommerce.
My knowledge is a bit old. There’s gotta be better tools available in the market.