Nitrogen in your tires is a very sensible thing but $295 is not. Tire stores and car dealerships charge between $10 and $15 per tire. That is, unless some other benefits like a tire warranty came with it. If so $295 might be a good value. I found this web site which give a great view on nitrogen in tires.
Nitrogen in Tires : Information about Nitrogen Tire Inflation News, Benefits, Generator Dealers, Location Finder & More
Bottom line...nitrogen is good and should become standard on Toyotas some time in the future.