I have used this place before my washer and dryer were connected in my house.
http://wonderwash.com.sg/
Coin-operated, self service, laundromat. They have German imported machines. They have a range of sizes, all self-dispensing soap, and all sorts of fancy stuff. A nice place and reasonable compared to per kg places around the city. It's in Geylang, but in fact a top notch place and often the owner stops in to check on things- particularly on the weekends.