Make sure you buy one thats been serviced at a mazda dealer that way you know everything has been done on time.. and if you can buy one still with some warranty.
The major services are every 40,000kms and the are upwards of $450 but all the other services should be below $280 so long as you dont have any extras needed.
They are a good car though.. and i'm not just saying so because i work for Mazda