I doubt you have any claim against Peugeot, but you might have a claim against the people you bought it from if they sold it to you with some form of warranty, which I doubt. You got it cheap in the ...
The good news is that the engines will amass huge mileages with little more than prompt servicing, while the transmissions and suspensions are also tough. But, there are plenty of things to wath out ...
A fouled plug could cause a misfire, but it should be resolved by changing the plugs. If one particular plug regularly fouls there could be a problem with that cylinder. It could be a number of things ...