As I was not able to find an affordable place in time after my landlord asked for his studio back, I will have to stay at a friend's place for a few weeks/ months. I will be crashing in his storage room. How much do you think I should contribute moneywise?

At the tender age of 45 and after 24 years in East London, I have to vacate my studio (been in this one 6 years) and stay at a friend's place in Finchley because I am not able to find anything affordable. ​ I am dreading the thing and it feels like a failure. ​ I will be sleeping on using his mattress on the floor and using his desk (I am using my computer because I am fully employed but work remotely). ​ In addition to paying for my food, the odd takeaway treat for myself andf him, how much do you suggest I pay for the stay (elec, water and inconvenience)? He has not mentioned anything but it is understood that I will pay something fair and I of course want to. His spare room is full of stuff from floor to ceiling (he buys and sells vintage things online) and I will sleep in a corner but I am grateful. The idea is that I have somewhere to stay so that I can work and look for a place to live. ​ I never thought that with a full time job I would struggle to leave in my area where I resided since 1999... I am single so have no dependents and he is in the same boat (not married). ​ Thank you. ​ ​