Yes, both AMZ.One and Optiseller offer a Free Trial.
AMZ.One is designed for Large Enterprises, Medium Business and Small Business.
Optiseller is designed for Large Enterprises, Medium Business and Small Business.
Pricing for AMZ.One Starts at $15/Month when Billed Yearly whereas for Optiseller Starts at $29.17/Month when Billed Yearly.
Some top alternatives to AMZ.One includes Jungle Scout, RankActive, Outrankio, Sellics, K-meta Tool, Ranktracker, AMZ Alert, AMZInsight, AMZRank and Semrush E-Commerce Apps (Sellzone).
Some top alternatives to Optiseller includes Jungle Scout, Cenports, SellerCenter, Zoho Commerce, Marketplace Manager, Equip, MyEasyStore, Epsilo, iSeller, SellerApp and Omnyfy.