An experienced welder can manage just fine with a cheap £150 Sealy/Clarke.
For a beginner, especially if you are wanting to deal with thin stuff like car bodywork. A more expensive machine using proper argoshileed rather than disposable O2 cylinders is much more forgiving (And satisfying)
This is the modern equivalent of the welder I bought some years ago.
https://migtigarc.co.uk/tecarc-prof-mig-c181-compact-mig-welder-241-p.asp
I have always been very pleased with it. They even supplied mine with a plug weld timer on request at very little additional charge.
of particular note is the low amps rage, this you need for thin metal.
Your cheap 180 amp sealley/clarke will often only go down to 40 amps (or even higher). Ok for shipbuilding (Until it overheats) but not much good for welding up ones MX5
Hobbyweld
https://hobbyweld.co.uk/ can provide exchange rent free cylinders so you can get propper gas without having to have a BOC/AP account.