You've gotten two great answers, below, so there's little I can add except to point out that on pp. 127 and 128 of BJA, you have charts that catalog the costs of making the next-best play (instead of the correct one) for a flat-betting basic strategist.

In the text preceding the charts, I discuss how you might make just one error, but how it could be extremely costly, or how you could make a whole bushel of errors, with the cumulative cost being entirely inconsequential, as John has pointed out.

It's very difficult to quantify what you've asked, because spread is vital, and the nature of the error(s) you make is even more important.

Don