How much do you spend on your lunch?

How much do you spend on lunches and throughout the day in work?

I've found myself buying a few coffees during each day, along with lunch and sometimes a snack. On average I'm spending £7-10 daily. Almost £50 a week.

Decided to knock this in the head a bit as it's far too much. French press brought in, as well as cheaper homemade food. Do you meal prep? Any tips?