We do pay for reasonably good matches. And many shadchanim expect or hint to that. some object though if the amount is too high.
If someone professional does something for you, it is simple sevorah that you should compensate them.
Obviously, you need to look at the effort – when someone simply matches by height and ratio of hat diameter to skirt length – he is not deserving much of compensation.
And Sephardim do not charge for the mitzvah at all. (like with rabanut, you should be able to charge for the missed professional time).