How do I retreive error codes on my 1996 ford taurus

Try going to autozone when they are not to busy. They will do it for free.

There are some OBD II scanners out that are under a $100 if you want to read the codes on 96 and newer at anytime without having to go to a parts store. Though I go to the parts store when the car will get there myself. Some parts stores will let you take their scanner home for a few minutes if you are a good customer too.