Not really what you want to hear I know, but I’ve had 3 now, finally ending on a Weber and the quality vs the £150 sorts I had before is day and night. By cheap, buy twice (or thrice in my case). Look for a second hand one if the budget is definite, but you’re at the wrong end of the season.
That said – if you’re fixed on new, and at that budget, go to a decent garden centre and look at them in the flesh even if you then buy online (the sin!) Go for a decent heavy grate and accept that it’ll be a 4 or 5 seasons at the most buy, if you use it as often as I do, and save pennies for a Weber next time.
Gas FTW – used 5 times this week alone, simply because turn a knob, press a button, come back 10 mins later and start cooking. Charcoal is great and I have one of them as well, but they are more effort.