It depends what it's for.
I spend around £120 for a week's shopping for the family if I'm careful. So in that sense, £50 wouldn't even get us through half a week. So for a family weekly food shop, no it's not a lot.
For a single item of clothing? Hell yes it's a lot.
Really depends how much you've got to begin with, how many people you're having to budget for (in my case there are 6 of us), and what you're planning on using it for.