Cheap means buying something obviously crappy, and only stupid people do that since they usually cost themselves more in the long run. For instance, a cheap person hires the wrong person to do a job, and winds up paying more to have a competent person have to fix the damage done by the first workman. Cheap means giving your girlfriend flowers picked out of a funeral home dumpster, and leaving the wrong sympathy card attached to them, That’s going to cost you a lot more than you just saved!
Frugality is entirely different. Being frugal means using your money well and not wasting. Being frugal often involves spending large sums on the right things, like hiring competent professionals to do a job, or buying a more durable, quality product that lasts far longer than a regular one.