Wow, quite a discussion.
Here are my two cents:
1) For those of you who aren’t sure of the ‘going rate’. Unless you are giving a gift, the ‘going rate’ is anywhere upwards of $1000 (from each side I think, but I could be wrong) as far as I know. This is if there was no specific amount stipulated beforehand. This is for most circles in NY/Europe/Israel as far as I know (feel free to post other amounts that are the ‘going rates in other places/circles).
2) I have(unfortunately) met many many shadchanim over the course of my dating career- it is very very rare for a shadchan to stipulate what his/her fees are the first time they meet you. It is general knowledge that a shadchan is recognized for their work thru a gift or payment and it is assumed that the shadchan will be paid if there is a successful shidduch.
3) As far as I know, there is no certificate, degree or license required in order to redd a shidduch. So (in my opinion) the discussion as to whether a shadchan only earns shadchanus if he/she is ‘professional’ is, to my mind, mute. Anyone can suggest a shidduch and anyone who does see a shidduch through to it’s successfull conclusion, therefore deserves shadchanus (assuming that he/she is the only shadchan that was involved and both sides recognize that).
4)The discussion about a shadchan ‘doing it for the money’ versus ‘doing it for the mitsva’ frankly, turned my stomach. Just because a shadchan wants to be recognized for his/her efforts does not mean that the effort expended was not L’shem Shomayim. Shadchanim (the ones that do get paid) ‘earn’ way way less than they should, judging by the amount of time and effort that they invest in each and every shidduch that they redd. Every bit of effort that a shadchan does is out of the goodness of their hearts, if they are lucky and HaShem wills, they may become a Shaliach and hopefully earn something material from it ($$). Every shadchan is happy for the people that he/she matched- just because they expect payment, doesn’t mean that they are in any way not happy for the people that they matched. Again, they just deserve to be recognized and paid and not treated like shnorrers.
Apologies for that long ramble 😉
As far as practical advice- why doesn’t OfCourse turn to the Mechutanim (Chosson’s side)? they might be a bit more menshlich then the Kalla’s mother.
Failing that, I would find a mutual friend/ relative ( I think this idea was mentioned above) who can mention to either the Chassan/Kalla or to one or both sets of parents something along the lines of ‘BTW, I met so-n-so (the shadchan) the other day, and I’ve a feeling that he hasn’t been paid… I just thought you would want to know, bc I know this can bring really bad mazal etc, you should really check if he was paid…’
O and I’ll second that great line posted by adorable: ‘Make my shidduch and I promise to pay you!’ 🙂