The cheap metal gates you get online/catalogue are "ok", they do the job, but they're nothing like the iron gates of back in the day! They're mild steel, fairly lightweight, sometimes the welds will need a rub with a file, and the cheap ones aren't galvanised, they're painted or powder coated, so any chips will rust.
Galvanised I would suggest is absolutely essential. Even more necessary where the gate is lightweight. I paid the expensive extra for all my gates to galvanised, after seeing the previous set rust away.