OBD Code readers

Recent threads about code readers have got me interested in obtaining one myself. Garage mate has an expensive SnapOn one which reads and resets codes on my 99 Diesel Hippo without problem.
Can anyone tell me if the el cheapo PC based ones on ebay for 12/15 quid will work on my Landy? I don't mind trying myself but I don't want to throw away any of the repair fund which will be needed soon, as nothing more has gone wrong for at least a week!

Ive had no luck with the cheapo eBay ones. Im saving my pennys up for a Hawkeye

Some info in me posts on this fred: http://www.landyzone.co.uk/lz/f9/elm-327-2001-td4-es-138027-2.html

All the cheaper reader/scanners are unable to read diesels before 2004/5 as diesels were not OBD 2 compliant until 2004/5. The cheaper reader/scanners will only read engine related faults so if you need to read and clear ABS, gearbox and some other none engine faults (petrol and later diesels) you will need a more expensive reader/scanner. I bought one of the Autel maxidiag units and this reads and clears engine, abs and transmission faults where my cheaper U581 reader/scanner will only read and clear engine related faults. The Autel unit cost about £170 and the U581 about £70 so I expect you get what you pay for.