IMHO, has nothing to do with cheap (although some may be cheap but that's irrelevant.)
Let me give you an example to help illustrate cheap vs not cheap:
Once in a while I go to this self-serve frozen yogurt place. I grab the size container I want, go to the particular flavor frozen yogurt machine, dispense yogurt in to my container. I go to the fixin's table (choc chips, nuts, stemmed cherries, etc) and scoop out the fixin's I want — especially a bright red stemmed cherry that I plop right on top of the swirl of frozen yogurt. I bring my container to the cashier (always young and cute at this place for some reason), she puts it on a scale, weighs it and tells us how much it costs. I pay the girl and she smiles at me.
There is a jar next to the girl labeled TIPS.
If that's the end of the transaction, I put the change in my pocket — no tip is required. Not a matter of being cheap; a tip is just not required. I'm not cheap.
However, say I pay her the amount required, she smiles at me, lifts up her skirt and pulls aside her thong exposing a lovely shaved pussy, takes the stemmed cherry off my yogurt, rubs it on her pussy and a little yogurt stuck to the cherry rubs off on her clit. She puts the cherry back on my yogurt, puts her finger on her clit to remove the yogurt that rubbed off there, puts her finger to my lips where, with a flick of my tongue, I lick off the yogurt — after all I did pay for it.
For the extra service I would leave a tip.
If I didn't — now that would be cheap.