All that matters is that they convert. There's no way to know they will convert outside of testing in an actual campaign. And you generally want to have a load of landing pages, multiple variations for each segment which you do A/B testing on. Buying a $20 template and sending all campaign traffic to a single landing page built on that template is costing you a LOT more than the price of the template.

Templates are overkill. They don't have good copywriting - lorem ipsum all over. And this is just start. Soon there will be animated websites section, aggregation of free tools and localstorage based tools.