I did shiitake using plugspawn. I drilled holes into fresh logs, hammered in the dowels, and seal them with wine bottle wax. No sanitizing or sterilizing involved if you have a large enough bit of biomass you are using to inoculate the substrate.>pressure canner>second hand shop.
I highly recommend you buy a brand new one. These things are super dangerous if they explode. You never know what one from a second hand shop has been subjected too. Older models may have been discontinued or recalled due to improper safety features. They can be deadly. I use a couple several times a year for food canning and I take no chances with them.