Supporting your local shop is a great thing to do. And if you can do that, go for it. But some of us need to pinch a penny or two, and that's where online stores, eBay, and even Craigslist come in handy. Keep in mind that "pro packs" (full packs of five rolls of film) often come at a slight discount if you can find them at your local shops and even through online stores.
When making your decisions, consider your project. It probably should have a consistent look that would leave older, expired films easily found on Craigslist off your list. You could want to stick with the same film for the entirety of the project, or you might want to at least stay within the same family of products, such as Kodak Portra films, but vary your speeds for greater flexibility if your project will take you indoors and outdoors throughout different times of the day. For this reason, you might find yourself with Portra 160, Portra 400, and Portra 800 in your bag.
Whatever your needs, despite the slow dropping off of certain film stocks, plenty still exist to give you the options you might prefer. And some companies are even bringing new films to the market (check out this page for more on that)!
We encourage any and all possible research online prior to your rental so you can be sure you're getting what you need. Eventually, the Beauty of Film section will be a much more filled-out resource for those considering various film types.