I paid several hundreds of dollars for my CNA certificate through a CNA School. The course was intense and packed with a lot of information! I found myself tired and frustrated a lot. 

I started working shortly afterwards at a local nursing home. There I met a friend who told me the nursing home where we were both employed had a class for CNAs there at a fracture of the cost and time. She took the class and enjoyed it very much. So before you spend a lot time and money in a course at a CNA school, check out the local nursing homes to see if they offer CNA classes.  CNA schools can be a great career start.  Good luck!