Yes, both nandbox and AppInstitute offer a Free Trial.
nandbox is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
AppInstitute is designed for Individuals, Freelancers, Large Enterprises, Medium Business and Small Business.
Pricing for nandbox Starts at $49/Month whereas for AppInstitute Starts at $42/Month when Billed Yearly.
Some top alternatives to nandbox includes Nwicode, Bizness Apps, GitHub, Apphive, AppInstitute, Native, AppMaster.io and Codeless.
Some top alternatives to AppInstitute includes AppYourself, Bizness Apps, A2Zapps, Apphive, Native, geekApps, 2OS App Builder and AppMaster.io.