01 Custody
Who holds the money when affiliates get paid?
Nobody holds it but you. Ambassly's terms say it does not itself pay your affiliates. You export a CSV or a PayPal mass-pay file and upload it to your own PayPal account. The money goes from you to the affiliate. Their pricing page prints no fee for that.
AffiliateRail is built on the same principle. The difference is who does the work. On Ambassly you run the upload each payout. On AffiliateRail the run is scheduled from the $59 plan. You approve it.