I won't go into all the detail of the lengthy, lengthy conversations we had about pricing over the course of a year before finally implementing it, but you're right that the price is low. However, that's intentional.

There are already products serving really big projects (the ones with costs in the hundreds of millions), but those tools are all far too expensive (and complex, slow, cumbersome, etc) to be used by smaller projects. We chose to make Woobius affordable to smaller projects too.

With respect to average size of projects, many of the tinier projects (e.g. a small house) will probably just about get away with the free version (but if they need a bit more storage, £10/m - or equivalent in other currencies - won't break the bank). Small-ish commercial developments will probably use around 1-3 gigabytes. Very large or very active projects are probably looking at 5-10 gigabytes.