It's already free for open source. If someone wants to use it for a commercial product, they shouldn't mind paying commercial prices. It's not as if $7 a month

It's already free for open source. If someone wants to use it for a commercial product, they shouldn't mind paying commercial prices. It's not as if $7 a month is a fortune. What you might want to do, however, is give people a free trial period of say 3 months.