How should I repay my boyfriend & his housemates for letting me stay there for 6 weeks?

I moved out suddenly recently due to an aggressive housemate and am going to stay with my boyfriend and his housemates (aged early-mid 20s) for 6 weeks until I move into my new place. I asked my boyfriend what I should do in return for the household, and he said I should contribute whatever I think would be appropriate. I'm not sure whether to propose a certain amount of money per week, or whether I should maybe buy some things for the house that they need, e.g. a microwave. What do you think would be reasonable for 6 weeks? I just want to make sure I'm not a nuisance, because I know it can get annoying having long-term guests in the house who don't contribute their fair share.