Personally, had the tyres just 'cracked' on me like that and they hadn't been sat for months/years, I'd have taken pictures and complained but I'm a consumer warrior.
Complain to who? The OP didn't purchase the tyres new, he doesn't know the history of the car. He also bought the car sold as seen?
Do you check the tyre pressures reguarly? The sidewalls often crack when they have a low pressure.
You can't blame the tyres on the car, you can't complain it was due for a cambelt. Exhausts need replacing on plenty of cars after a certain mileage. The only "freak" repair, may be your alternator problem. All cars have have faulty parts, that need replacing after miles of use. You're just upset you didn't budget for the majority of those costs and they happened whilst you were unemployed, all at once.
It's a shame French cars aren't able to do normal mileages without having everything go wrong. I guess coming from a Honda I didn't expect to have so many issues! That was approaching 100k and I only had to replace wear & tear items like brake pads and tyres.
Not long sold my 16v W reg laguna to a mate, its now on 151,000 miles. I had it since 92k(4 years ago) and all i've had go since then is two rear wheels bearings. Usual wear and tear items like tyres expected/general servicing. 1 owner before me with all Receipts/full renault history, original clutch/gearbox, still runs beautifully.
Few German cars at work(only a few years old) seem to go wrong all the time, BMW 120i keeps having new injectors, also had a new steering rack/windscreen washer pump under warrenty.. He should have bought my £800 Renault.
It just seems to be if you get a good car no matter what make it is.