The economics of couch sharing versus a monthly room
A couch may cost little in rent, but it can carry other costs: contributions to the host, storage, transit, meals out, lost sleep, and time spent moving between places. It may also make work and job searching harder.
A monthly room brings a deposit and larger fixed bill, but it can provide a lockable space, predictable commute, better rest, and a stable address. Compare costs over several months, not one week.
If couch sharing is helping you save toward a defined move-in date, the trade-off may make sense. If it has no end date, price the instability honestly. Cheap housing is not always low-cost housing.