In the infrastructure purchase screen there's a typo in the description below the table:

If I'm not mistaken, this is supposed to read 50 levels, with the minimum you can buy at one time being 0.49 levels.

I can provide a screenshot too if you want one, just let me know.

I think that is all that you can afford right now. I show a considerably higher number. Try again after you collect taxes and I think it will increase.

Ah, I never thought of that, it is probably going to be that. However, the wording of the sentence was slightly misleading.

This suggests that the maximum that can be bought is 0.49 at any time, rather than at this point in time. I'll check it again tomorrow, and post on whether it's actually a problem or not.

Fred was right, it increases with money avaliable. However a re-word might be worth thinking over to avoid confusion.