1998 Plymouth Breeze Car won't start

Hi guys, my 1998 2.4 litre breeze has 200000 kms on it. I was driving it and stopped and put it in park. It shut off and wouldn't start up. I checked the fuel pump, fuses, and she was getting spark. Someone suggested timing belt had failed. If this is the problem how how hard is it to change a timing belt and how expensive is it if I cannot do this job myself? Thank you