It depends how deep you wish to view things. Probably the best real deal would be to buy a Snap-On MT-2500 scanner on ebay and then buy the MB module new. It hasn't been out long so it probably would be hard to find the module used. The 2500 cost near $4000 new but there were billions of them sold (or at least a lot by any scanner standard). I think the MB module is about 500 new.
This would give one a very competent tool for most of that car and most of all models through the 2000. Fault codes, actual values including graphing capabilities, activations, and some adaptations.
I think one could do this for about a grand. The other tools to look for on ebay would be a Baum CS200 and the AST Retriever. I doubt you could get one for as little as the Snap-on. There are always Snap-On scanners on ebay.
Bosch Master, ASE Master, L1
33 years MB technician