It Depends. You can get a perfectly usable bike light for £30-ish these days, which is fantastic- whether it’s a Torch or a magicshine or whatever. It won’t be amazing but it’ll be more than enough to go riding.
You can spend £80-ish on something like the Magicshine MJ-872, which is a little old now but is still a great light- well made, excellent beam pattern etc. It’ll hold its head up in any company and if you look after the batteries should last years.
Or, you can spend a fortune… And possibly get something really, really good. Or, possibly get something no better than the Magicshine option for several times as much.
But yeah there is a bewildering amount of choice. Which is good, these inexpensive lights didn’t exist when I first asked this question.