I'm in the process of looking for an ODB II tool as well (ODB II for 1996 and later).
"Code readers" just read codes and can clear the codes. So they are a little better than me cycling the key on and off three times and finding the text for the code on my PC.
"Scan Tools" have the code reader functions, plus the ability to read real time data from the ECM and the capacity to turn switches / relays / solenoids on and off as part of diagnostic tests. A very neat feature, as it allows you to individually turn off the solenoid to each fuel injector, making it very easy to determine if the fuel injectors are the problem and which one. How similar it will be to the factory DRBIII tool capacities I don't know.
The Smarty POD has code reader functionality built in. :-laf
The more tradional, low priced, generic code readers that you can find at Action Auto, Autozone or Sears are made by
Actron.
I'm waiting for the Actron Scan Tool CP9180 to go on sale. They list for 230, internet 130. An earlier model CP9145 originally listed for ~230 and now is ~80 on the net or Autozone. You might check out the users manual on the Actron site to see if it will meet your needs.
Since a dealer charges 80-120 just to hook up a meter to run the diagnosis, then everybody should probably own a generic one.