This is another easy task to do for a Toyota Prius 2012. In most cars changing the air filter is a pretty simple task and all you need is the air filter and know where it goes. Every 12,000 miles I change the air filter in my Toyota Prius 2012.
Here a few things you'll need, I normally wear disposable rubber gloves(since you'll be under the hood, not for very long) and the air filter which you can pick up at Amazon. The filter I decided to use for my car was the FRAM CA10741 Extra Guard which you pick up here:
According to the box, it should be replace every 12,000.
Once you have the part and are ready, just pop the hood, and you should noticed the air filter in the front. Once you located it, you can pop off the cover and it should be straight forward to replace it. Here is a great video on how to replace it on youtube:
Some of the maintenance I've written about is simple for the Toyota Prius and hopefully will save you money.