Hi looking to buy 500x 1.6 diesel has any one got any tips or advice it would be helpful before I purchase one

Nothing much apart from the usual - make sure it has FSH / both keys etc. My wife has the 1.6 MJ Cross Plus and its been pretty much faultless for two-three years/30k.........
The early cars are 4 years plus now so depending on your budget - if you go for one of those be aware Fiat state a 4 years cam-belt change so make sure its done or getting done.