For years I have dumpster dived bags of sprouted potatoes discarded by grocery stores, both to eat and to grow. Each fall through late winter here in central Florida, or early spring in cold climates, just ask your friends to save their sprouted potatoes for you vs. discarding them. Cut them up into chunks, with one sprout per chunk, let dry in the shade a day or two to heal the cut surface, then plant them about six inches deep in loose, rich, slightly acidic soil. Any variety works.....Russets, Idaho, Golden Yukon, the rare blue potatoes, you name it. Many gardeners are shocked to see the price of "seed potatoes" in catalogs even before shipping costs...this is a free alternative. You can also buy untreated potatoes from an organic market and let them sit in a north window sill until they sprout and do the same thing with them. In the last week I have planted several potatoe patches in containers...by April I should have oodles of thin skinned FRESH "new potatoes".
I will soon post a full article on this topic that ran in The St. Petersburg Times some years back to give you both more detailed planting instructions plus a simple savory recipe. Enjoy, John