Accomadation for three days

Anyone recomend AS INEXPENSIVE (lol) as possible for several days just to open an account in singapore? Only one person thx

You can get a dormitory bed in a backpacker hostel for S$30/night, if you don't need privacy. Rooms in cheapo hotels cost S$60/night and up.
FYI: It is illegal to rent out private rooms to tourists, and those who still do that are most likely out to cheat you - avoid such offers even if the price looks tempting!

Yes, do not rent a room from a local as you need to stay a min of 6 months or it's not legal. Stay at a cheap hotel, cost around $60 per night. Very good and clean rooms for that price.