Well I was looking at those A class Mercs as you can find decent ones for very cheap. Cash, you will struggle to get them financed. But a mechanic said stay away. Starter problem, remove engine and gearbox, alternator problem, remove engine and gearbox to fix.
There is a reason you can get them so cheap, very expensive to fix anything. Same with older BMW's, you can get them cheap too.
Fair enough.
I got a problem child from WBC that was really neglected for <R28k. Changed plugs and HT leads and ran an engine flush then worked through the laundry list of bulbs, wipers and drop-link (completely missing), got it through CoR 2 weeks later.
After replacing the wishbones the door started machine gunning: common problem. There's a Saffer that has a youtube tutorial to fix a W164 which shares the same lock parts. The boot lock is also a common issue, but a screwdriver and flashlight to find the red tab and it'll open and they're cheap on AliExpress.
Ok, the W169 and W245 are not pleasant for what is considered easy jobs on other cars. Starters aren't common, but while you're there you might as well do a clutch, replace the idlers on the accessories belt and do the chain (
long oil changes kill chains, doesn't matter the brand; new BMW diesels with very high intervals are a danger for this out of warranty). Yes, an absolute cow because you take the entire engine out (think porches) to get to anything that isn't a regular maintenance job.
I was so impressed with the first W169, I bought a auction A200 auto high spec for R14k as a project car to replace my dad's LR3 (big, heavy and too expensive for a retiree) -- rinse and repeat the first car's issues and pulled the engine for the CVT to be redone and replaced the timing chain because that was done for, and the water pump because why not. His only complaint was it was smaller than his tank, but otherwise simple to drive and should see him through for many years. Perfect old people car because of the high seating position. Finding a bullet under the rear bench was a special moment while detailing the inside.
If you are mechanically and electronically handy and have a spare old notebook and spare HDDs (because everyone should be on SSD now), then don't be afraid of older cars.