I have a 2008 yaris, about 175K miles on it. Bought it from the original owner with about 125k miles. Owner told me all he had to do was replace the water pump. I haven't had any major issues at all with mine. It's been the most reliable car I've ever had. It's an actual Toyota made in Japan, before Mazda started making them. I highly recommend it as a cheap, reliable little commuter car. I love mine, and with the 5 speed like mine has it's actually quite fun and zippy. 

I'm not really hot on the Yaris myself but it seems like they've gotten better over the years. If your looking for a car and want to see if you can find a better deal check out Autotempest.com that should help you in your car search. GL! 

I got a 2003 Vitz, which is the Japanese version of the Yaris. Other than regular maintenance and some simple repairs, the car has been running decently enough, considering the amount of mileage I put on it yearly.

Like our old buddy says: have an honest mechanic check it first, and if he says it's in decent shape and the price is right, go for it.