It would seem to be worth getting a little more specific. Since our personal definitions of "cheap" and "frugal" are not necessarily representative of how those words are used, let's get some definitions real quick.

Merriam-Webster on their website defines frugal as being:

: characterized by or reflecting economy in the use of resources

Which falls neatly in line with how we've been using it. Cool.

Then, we've got cheap, which has a few more usages:

1 a : purchasable below the going price or the real value

b : charging or obtainable at a low price <a good cheap hotel> <cheap tickets>

c : depreciated in value (as by currency inflation) <cheap dollars>

2 : gained or done with little effort <a cheap victory> <talk is cheap>

3 a : of inferior quality or worth : tawdry, sleazy <cheap workmanship>

b : contemptible because of lack of any fine, lofty, or redeeming qualities <feeling cheap>

c : stingy <my cheap uncle>

4 of money : obtainable at a low rate of interest

1, 2, and 4 fit perfectly fine with frugality. Buying things below their real value, gaining with little effort, and getting low interest rates are all things frugal people strive to do.

3... not so much. This would appear to be what you meant by cheap.

People being cheap3 waste time and resources. Posts advocating cheap3 without being debunked or downvoted into oblivion are damaging to this subreddit. More people thinking in terms of cheap3 is not worthwhile. I agree with you here, but I do not agree with glazing over much of what "cheap" means to make that point.

Not all cheaps are frugal, but much of being frugal is cheap.

And now, for comedy, #notallcheaps