I knew a fellow who went in with his brother and they bought a light twin together. They did a lot of their training in it. When they were done, they sold it for what they paid for it. Free twin airplane! (But of course they had to put up the money in the beginning.)
Looking at it from the opposite point of view, it should be mentioned that if there are any mechanical problems with such an airplane, the "owners" have to pay for them out of their own pocket. It seems the minimum price for anything that goes wrong with an airplane nowadays is a thousand dollars! And what does insurance and an annual cost nowadays? How about engines that have a high TBO (time before overhaul)? The nice thing about renting is there are no maintenance costs (which can be huge).
Twenty years ago, we used to say a light twin will cost you $40,000. If you buy one for $20,000, guess what? You will spend another $20,00 getting it ready to fly. How much would that figure be today?