Sometime in July I planted sweet potato slips grown from a store-bought potato, as well as some peanuts, from a grocery store bag as well. The sweet potato harvest in a picture below is just from one slip; and that's what you should expect usually, six to ten potatoes from one slip. Sweet potatoes are pretty undemanding, they will grow in slightly fertilized sand, in fact these grew in just that, very poor sandy soil.
Peanuts do not demand awesome soil either, as a member of legume family they fix their own nitrogen. The harvest in this picture is just from one peanut. Not a bad outcome, somewhere from ten to twenty peanuts from one. I imagine, if I plant a pound of peanuts next year, I will have twenty pounds harvest, that will make a huge bag.
I tasted one peanut and it was still quite raw. The kernels should be somewhat darker in color; and the plant leaves themselves should turn yellow or light brown, indicating that the "children" are taking in the nutrients. I will give them another month, after that I will take another sample. Peanuts are an indeterminate vegetable, so we cannot count on a 100% maturity; as long as most of the peanuts mature the harvest should be deemed as a success.
The beauty of a garden is that once you grow something, it will always be there. I have tons of volunteer tomatoes, peppers, dill and bok choy. Sweet potatoes and peanuts are self-propagating as well. Since it is impossible to dig out every little root, they will continue giving for the seasons to come.