I'm looking for an app/platform to reimburse volunteers for a nonprofit. I've looked at Square Cash, Paypal, Venmo, etc., but they all seem to limit transactions on a monthly basis and are geared mainly for personal use. Thanks in advance!
They're not volunteers if you're paying them, and you'll want to use some kind of bookkeeping software in conjunction with the payments. You probably need to bite the bullet and use a payroll company.
PayPal's P2P transfers are free and have a high limit. Zelle might also work for you.
I've done a lot of work in payments and there just isn't a great, no-limit solution for consumers. It's because they want to charge the higher-volume users to make up fot the free users.