The are 6 different ways across 3 unique modes of transportation to help you travel from STR to MRS. If you're only considering the price, you should check out the train out of Münchingen towards Cabriès, as it is the cheapest to MRS. It's common to find tickets for as low as $139. Train from STR to MRS, it will get you there soon enough!
On your trip from STR to MRS, it is best to book as soon as possible. It won't necessarily help reduce your price by a large amount, but will ensure that you have a spot on the bus or train. Shuttle service may be available to MRS. If you're traveling with a large group, you should probably take a shuttle as it will reduce the price per person. Alternatively, there are shared shuttle services available. With this option, you'll want to book as soon as possible to allow the shuttle service enough time to coordinate your pickup and dropoff.