The Software Centre should be context-sensitive, so when you're looking at an app where price == 0.00, the option is to 'Install' with the price text shown as 'Free', and if price > 0.00, the option is to 'Buy', with the price text will be shown as the price.
The Software Centre should be context-sensitive, so when you're looking at an app where price == 0.00, the option is to 'Install' with the price text shown as 'Free', and if price > 0.00, the option is to 'Buy', with the price text will be shown as the price.