The best and cheapest way can be a low-end VPS but you should increase the resources as in time your audience grows up.
One of the most important thing you should consider is the SSL.
Because you want your visitors to rent a car, you would probably have a payment infrastructure for your website, which needs SSL.
Please search for "cheap cloud hosting" and start checking the results one by one.
Consider, if the company provides you free or cheap SSL or not.