No, all point updates are available to users free of charge. You only have to pay for upgrades when you move from one major release to another.
For example, if you move from Gaea 1.0 to Gaea 1.1, your upgrade is free. But if you move from Gaea 1.0 to 2.0, you need to pay for the upgrade. Existing Gaea users receive an upgrade discount when moving to a new major version.