We ran a 206 1.1 from new as 'er car (sorry sold it 2011
Good general car but here are bits i can think of. Bear in mind this was a looked after 1 owner 80,000 (IE 8000 a year) car. It was a 2001 Y.
Electric fan failed twice (shaft corroded and fan fell off) so they obviously only last 4-5 years. bypass temp switch or let it tick over for 15-20 mins from cold to hear it run (very noisy if about to fail). Young driver wont notice this and will boil the engine.... Its an £80 part, 2hrs labour if you cant do it yourself (although I could do it in 45 mins now).
Electric window switch wore out (fitted 2nd hand one)
Indicator stalk wore out (fitted 2nd hand one)
Cambelt interval revised by peugeot. Check in google but a lot failed early so anything over 80,000 thats not been done or 10 years DO IT. Its an easy one to do, no special tools required.
Most importantly they have a weak gearbox, shared with the 1.4. We swapped it ourself for a recon one at 65,000 although it didnt fail it was very noisey and full of metal residue (like I was changine oil once a month and it was still overwhelming the magnet).
There were other bits like CV joints and a cat. Overall although I felt it became an expensive car maintainance wise (bearing in mind the milleage and it was service at peugeot for 5 years and anually by me after that) it was good MPG and never really let us down totally...
(edit: just remembered a coil pack (expensive) but that did illuminate the check engine light so would be obvious when buying. that may have poisened the cat althoguh we didnt drive it more than a few miles before replacing...)