Could I pay by the number of Blocks usage, except subscribe by month?

It seems using Blocks needs a Pro account.
But so far，I don’t think I need to be a pro.
If you can offer a choice,
just like $2 / 3blocks & $10/20 blocks,
may be I want to try.

and I think the more people buy for blocks, the more will subscribe in the future.
&& developers may also built the 3rd party Blocks,then earn money from the usage of their Blocks。