While I admire your pluck Mr Accy, they're not a good buy used. I got lucky and shopped around for a while and found one with only 40k miles that had just had a full engine rebuild at a Mercedes dealer. The owner had clearly had enough, and were cutting their losses. I spent 2 and a half hours going over it, pulling up carpers, pulling off panels, jacking it in the air, checking steering and bushes for play, even compression testing it before I was happy. Having got a good one they require specialist TLC to keep them going - not a problem for me doing it myself, trained as I am by my Dad as a vehicle (wheeled and winged) engineer from about age 4, but for most folk that means either a Smart specialist (not many about) or Mercedes dealers (loads about, but very expensive). So, while I love them I would warn people off them as a used buy unless they're really, really, utterly sure what they're getting into. They do get maligned for safety, but in 2004 when mine was made NCAP tested 15 SUV's in the same year - the Smart recorded better rollover protection than 14 of them, and a higher score overall as standard than all 15 (although spec'd with optional extra safety systems some of the SUV's scored higher), so don't be put off on that score over another car of a similar age. No, it's generally caring for them that requires attention and undermines them as a sensible used buy.
The later Mercedes type W451 model from late 2007 to 2014 is mechanically more conventional and uses a Mitsubishi motor, so is a more affordable proposition as any halfway decent cro-magnon man or woman with a spanner can care for them . Avoid the MHD at all costs - I can not stress enough how strenuously the MHD should not be considered. The turbo versions are OK, but why buy into extra complexity and expense? Avoid the diesel, it's the same diesel as the previous generation but with the added (un)benefit of a DPF and they're nasty, very prone to problems. If you're on a budget, do most of your journeys solo, want minimal running costs, and the ability to park in the slightest hint of a gap then the 1.0 non-MHD W451 is the one.
The current generation W454 is great, but still expensive new, costing from 15 to 29k! Used prices are reasonable though, but still not exactly in budget car territory.
Of course, many youngsters will turn their nose up at them. However, for young men at least there is a major upside to Smart car ownership - it gets female attention wherever it goes, particularly mine being the cabriolet. I don't think I've visited a petrol station yet without some young filly coming over and chatting about the car. Now, I'm a happily married near-50 but a canny 18 year old male, denim shirt slashed open to the waist, medallion shining brightly, will capitalise on the female attention. "You like my little Smart car, eh? Fancy coming for a spin?", and then winking playfully at them.
