Yes, both FastSpring and plug&paid offer a Free Trial.
FastSpring is designed for Large Enterprises, Medium Business and Small Business.
plug&paid is designed for Medium Business and Small Business.
Pricing details for both FastSpring and plug&paid are unavailable at this time. Contact the respective providers for more information.
Some top alternatives to FastSpring includes Chargebee, Paddle, BillingPlatform, ChimpCharge, 2Checkout, EBizCharge, ReCharge, plug&paid, BigCommerce, Selly, PayPro Global and Web.com.
Some top alternatives to plug&paid includes and undefined.