Rule of thumb is that a processed wafer from 28nm and older is around $3k/wafer and the cost goes up kind of exponentially towards the smaller nodes. Also, in general, the fab wants you to order a "FOUP" of wafers at a time - that's 25 wafers at a go.
Is there a service to get on a FOUP with a group of people? I know for example of Tiny Tape Out [1], but I'm wondering where you might explore for larger designs.
