The youtube link is neat. Too bad they are out of business. I think writing my own open source software may be best. The time is worth a lot more than $1,000 though. I'll dream up a system here and maybe copy it to a new github project later.
Private Key printer:
Offline/airgap private key kiosk that accepts $1 bills or a store owner PIN. No screen, maybe 3 buttons for BTC, ETH, and LTC. Based on a $200 Minix NEO or Rasberry Pi and a cheap laser or thermal printer.
They can skip this PK printer if they bring their own smartphone or paper wallets or generate their own PKs at home.
Public Internet PC:
Hardware:
Minix NEO Z83-4 Win 10 PC, $200
No printer
QR barcode scanner, $40
Touch screen, $150
Software:
Touch screen windows shortcut buttons to
https://www.myetherwallet.com https://blockchain.infoand similar wallets that accept scanned public and private keys.
Touch screen conversion calculator linked to coinmarketcap.com with easy buttons to convert $20USD.
Pen and paper or $70 Brother Laser for note taking. They can also email themselves.
Warning Sign to not generate PKs on the public PC and to spend full wallet after scanning PKs.
They can skip this PC if they have a smart phone and know how to use it.
Funding PC:
Shop owners existing PC and cash drawer
They can use Coinbase, trezor, or whatever they want.
Requires a little training, but involves exchange profit and customer interaction so they would learn quick.
Physical vault:
Maybe some customers would ask them to store their private keys in a vault or safe deposit box. Customers do it with gold diamonds, and guns, so why not private keys?