Code reader

I have a 97 K2500 454 4x4 which ever since I have had the vehicle (2 years now) has had the "service engine soon" light on. I have read the Gas Cap Code on this site and realise that to find out for sure what is going on I need a code reader, therefore I have been looking on evilbay but the only ones I have seen say they only do up to 95. Is there anywhere I can purchase a code reader that will do my vehicle and would I plug it in to the harness just below the steering column?
There are not many dealers over here that would even know what a Suburban was let alone know how to work on one, the nearest one to me that I am told is any good is over 150 miles away.

You can get a very basic code scanner for around $50. It will display stored error codes and reset the lamp. Just look for a generic OBD-II code scanner.

Check on Ebay for an Actron P9145, they usually go for $125-$150. NIce scanner, and it will read live data so you can leave it hooked up and look for gremlins that sometimes don't show up unless you're driving it. I've agonized for two years about buying one but haven't shelled out for one yet. Good luck...:)

Thanks for the information. I have now found loads of them on evilbay (put in scanner rather than reader). Will let you know which one I go for and if an idiot like me can use it or not.