Most shelters have some sort of paperwork that answers some of your questions. Shelters are often very busy, somewhat chaotic places so it can be hard for them to answer messages, especially with all the shutdowns. Check their website for an email address for their foster coordinator/volunteer or for fostering resources like a welcome packet.
You could also look at some of Maddie's resources https://www.maddiesfund.org/flash-classes.htm
If you have no luck there, I'm not sure if they'll give you a discount but I know some shelters do a buy one get one discount on kittens. Most shelters operate at a financial loss each year so they really have to pinch every penny. Kittens usually stay in foster care until they are 2lbs (min weight for them to be spayed/neutered) which happens around 8-10 weeks. It costs about $150 in food and litter to raise a litter of 5 kittens and their mom and that doesn't include vaccinations, medications and surgery.
Hopefully you can get a hold of someone. I bet email will be more effective. Good luck and thank you for fostering, it really does save lives : )
#AdoptingaPet