If you're not sure if you're using features that are Enterprise features, this system view can help:
https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-db-persisted-sku-features-transact-sql

Even before it was completely free, Developer edition was relatively low cost in SQL Server 2012 or earlier, I remember it being like $50 or $60.