Here's my idea: There are two reasons not to use potatoes from the store as seed potatoes.
1. They apply a chemical to prevent the spuds from sprouting, and
2. They're not certified seed potatoes.
So my idea is to plant those store bought potatoes in the fall and let the seed potatoes rinse off over the winter in your garden bed. If you grow potatoes and miss some while harvesting they will grow the following spring. So I'm assuming that if you put potatoes in the ground in the fall they will also sprout in spring. I can't argue the merits of using certified seed potatoes. But for the price difference you may decide it's worth the risk. That's up to you. But I would say that if you continue to use potatoes from your garden as seed for the following year you'd be increasing the odds of creating problems. But that's true whether you used seed potatoes or store potatoes. You also have to gamble on how much blight, for instance, is in the fields where store potatoes are grown and where seed potatoes are grown. I do know that a field of seed potatoes is permitted to have some blight, a low amount, but if that's true then you can get blight from your seed potatoes. What I have no idea about is how much blight is in the fields where my store potatoes are grown.
I have a potato sitting on the window sill, which is were this idea sprouted from. ( sic ) The potato is a store potato. I put it there to see what would happen. When I was a kid our potatoes started sprouting as spring approached. The sprouts would get a foot or more long, sometimes 18" long from potatoes in the heavy paper sack they were sold in. The potatoes were in the dark in the back corner of a cabinet. So this potato has been on the sill for 6 weeks or more, maybe two months. I considered planting it when it started sprouting; which it did. I sometimes think of rinsing it off, a couple times, soaking it overnight, leaving it out in the rain. But whatever occurred to me was dismissed cause it's too late in the season. But now, the season is next spring.
However you plant your spuds, please rotate your crops, don't plant spuds in the same garden space, some say every other year, some say two years, some say 3 year rotation. Take your guess.
The advice I give to new gardeners is to start out with commercial certified seed potatoes, then save your own potatoes for seed for the next season. The reason for this is blight. It is too easy the introduce blight into your garden, and once there, it can be a problem for years. It can mean that you will not be able to grow your own potatoes.
It's never too late to start! I retired to homestead on the slopes of Mauna Loa, an active volcano. I relate snippets of my endeavor on my blog : www.kaufarmer.blogspot.com
Companion Planting Guide by World Permaculture Association