Recs for Chinatown
The least expensive, and often the best tasting, way to get BBQ pork and roast duck in Chinatown is to stop in at one of the BBQ stands, choose your meat, ask for it to be chopped, and get it to go to eat on the street. You can ask for napkins and a plastic fork. The ducks will be hanging in the window on display and you choose the one you want. For the pork, you can ask for lean or fattier pieces or point to the exact slab you want. Some will have a table or two crammed in where you can sit down and get a rice plate. One would be New Moon on Stockton St. Prices per pound or piece are usually posted on a board overhead so you can readily determine how much you'll spend.
New Moon Restaurant
1247 Stockton St, San Francisco, CA 94133