There are a lot of complicated designs out there for motors using permanent magnets. Search Google for "permanent magnet free motion machine". My idea is relatively simpler, maybe the other designs have plusses or minuses, i dunno. i guess that's part of the learning curve. Some other designs:
My idea is closest to the last one, but the middle is a little different.
there we go, the radial magnets repel, the shaft spins. that's about it. Second thought, the blue one, where is it..
That's made from bar magnets, which are 50 cents here: https://www.xump.com/Science/BarMagnet.cfm, so i might go for that. Radial magnets are practally inexistant online.