$871 - Flights to Saigon, Vietnam from San Francisco
Cheapest flights fly out on Wednesdays or Thursday, but try searching for flights on other days of the week as well. 7 day vacations seem to the cheapest (so that you fly in and out on Wednesday), but these prices have been going down recently, so you may be able to find discounts on other days of the week as well.
Saigon is now officially called Ho Chi Minh City, but the airport code still alludes to the name being Saigon - SGN.
Stopovers are often in Seoul, Bangkok, Hong Kong, or Tokyo. Flight time for one-stop flights is usually under 20 hours, between 17 and 19 hours each way.
Flight price includes international fees, taxes, and other surcharges. Many sites don’t include these fees when they quote airfare prices, so be sure to incorporate these fees when comparing flight prices.