Changing your in air cabin filter is pretty simple task. It only takes 5 to 10 minutes to actually change the in cabin filter. I have been to the dealership and they are looking to charge anywhere from 60 dollars to 90 dollars, to save some money and time, you can do it yourself. How ofter should you change it? I change mine every 15,000 miles, but I believe this all depends on your environment. If you car is driven in a rough environment, you might what to change it sooner.
The filter can easily be found on Amazon, here is the in cabin air filter I use for my Prius 2012:
Amazon has a deal to pick up the two pack which saves you money. This the part I use for my Prius 2012. I've read a few reviews online and this seem fair for the price. Once you get the part, it's pretty straight forward to replace, here is a good video on how to change the in cabin air filter for the Prius from 2010 to 2015:
As you can tell, this is pretty easy, hopefully this helps someone change their in cabin air filter and save some money.