For me, there comes a point (somewhere around the £2k mark) when the value of the car is a relatively minor consideration. You buy the car for transport, and the money you spend on buying/running/repairing it merges into one. You buy a cheap car in the knowledge that it may need fixing more often than a newer one, so should be prepared to spend out a larger amount on repairs and maintenance relative to purchase cost.
If it does the job you buy it for, I still think the Multipla is a bargain. I've posted on here before about its' dire residuals compared to something like a Touran, but that is what makes it such a bargain. Just have a look at what you'd have to part with for a Touran of the same age/mileage. The only thing that comes close for value is a 307 SW.
Example: The car I owned befroe the Multi was a 27k miles 54 plate Mondeo ST TDCi estate that was really fully loaded - whoever ordered it (it was a Ford management vehicle) had taken a long trip down the options list. List price new was just over £30k. I bought it from a Ford dealer at 11 months old with an extended warranty (out to 5 years/unlimited mileage) for £16k. Now that's what I call depreciation.
I thought that someone else taking a hit like that, I would be protected from the same thing happening to me. Only partially true. I sold the car privately 3 years later with 45k miles on it for £7,200, so I lost nearly £9k in depreciation (£3k per year). Ouch. That's before the running costs are considered (though they weren't too bad as it turned out). Cost per year was around the £4k mark I reckon.
I bought My Multipla 3 years ago as a one owner car, about 4.5 years old, 107k miles and FFSH for just shy of £2.5k. It had just had a s/h engine with 60k miles on it and a new cambelt. Value now? Probably osmewhere around the £1,700 mark. Depreciation over the 3 years of around £250 p.a. - that's less than 1/10th of the Mondeos'. In hard cash terms, the Multipla has cost me a whole lot less than the Ford.
That's why I don't begrudge having to have a new clutch not long after I bought the car and I've just splashed out on having the front calipers and steering rack reconditioned, all new discs/drums/shoes/pads/cylinders/adjusters, all filters changed and a few other bits sorted out. Parts are dirt cheap if you shop around and (apart from the clutch) it doesn't cost a lot to have the work done.
Just my 2p worth.