The males owner do they get anything for "lending" their dog for mating?
The owner of the stud dog will charge either a stud fee or they can ask for a pup out of the litter.
What is it that the girls owner have to pay for breeding?
What don't they pay for
I've never bred a litter so I'll probably miss some stuff out but off the top of my head you have : health tests for the bitch in question, stud fee,travelling expenses to said stud dog, extra food that the bitch will eat and obv for the pups after they are born, worming tx, flea tx, a whelping box, vet bed, equipment for a whelping kit(thermometer, dopram V drops, scissors, feeding bottle etc etc), any vet treatment for the bitch and/or pups during and after whelping(and if the bitch needs a C-section, that'll set you back a fair bit), registering the pups with the KC.
A lot of that stuff have been paid for before you even know if the bitch is in whelp so you could be looking at spending a fair bit of money only to find that there will be no litter. You also have to think about the emotional side of it - possibly having to hand rear pups, the possibility of bitch and/or litter dying during whelp etc.
Have a look at our FAQ's on the subject
Here and
Here If you are considering breeding(even if it is years away) get yourself a copy of The book of the Bitch. It's a really good book and is very informative