Good questions! Here is my take:
Cardano is a platform to develop secure smart contracts. What does that mean? Think of it as an environment where you can build apps. Like AppStore of sorts but much more powerful, global and not owned by any corporation. ADA is a native currency of Cardano platform. It basically fuels any activity that takes place on it. It guarantees that your transactions take place, it make sure that your apps have enough resources to run and provide their value to customers. In short, you need ada to run things on Cardano’s provably-secure network.
Ultimately, the value of ADA will go up because people will need to ‘house’ their smart contracts on Cardano’s network. It could be something silly as cryptokitties or an entire financial structure of a country (you can create a virtual bank for example). Again, every interaction that your system has with Cardano network will require ADA to run it and that will drive the price of ADA in the long run.
Why will ADA win the race? Because it is the most serious piece of software ever created in the cryptosphere. It is secure, it is fast, it is interoperable and it is developer-friendly. In 6-12 months we will have a cambrian explosion of smart contracts on this platform because no one would want to develop anything on Ethereum or any other less reliable networks. This will drive the price of ADA in the short run.
As far as I know you can develop anything for free, but if you want to use Cardano blockchain resources for any of your needs you will pay minimum transaction fees. I think this is a fair proposition. If your business generates enough revenue, you will more than recoup your investments. If your idea isn’t that great you will come up with a better way to make it work.
EDIT: replaced itunes with AppStore–a better analogy.