Yes, both Chargebee and Proof offer a Free Trial.
Chargebee is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Proof is designed for Medium Business and Small Business.
The starting price of Proof begins at $26/Month when Billed Yearly, while pricing details for Chargebee are unavailable.
Some top alternatives to Chargebee includes billwerk, Subill, Zuora Billing, Billsby, ChimpCharge, Fusebill, ReCharge, Recurly and RevenueCat.
Some top alternatives to Proof includes and undefined.