"Pay-for" vs. "for-pay"

Solution 1:

The usage stats from the Corpus of Contemporary American English (COCA) and the British National Corpus (BNC) look as follows:

            COCA    BNC      

for-pay      22      0
pay-for       0      0           

In other words, pay-for is not an option on either side of the pond, while for-pay is only used in American English.

The most common collocates are services (3) and version (2). There is not a single cite for a for-pay product, but then again the sample size is very small.

My personal advice: while for-pay is self-explanatory enough to be used in informal contexts, in formal writing you might wish to reword. There isn't a single one-size-fits-all adjective; depending on context anything from commercial to premium might or might not work. You might have to restructure the entire phrase ("available for a fee" or some such).

See also: What is the opposite of “free” as in “free of charge”?

Solution 2:

People say "for-pay", but I think a real word like "commercial" or "professional" would be better.