Is there any reliable used car dealers in the market specifically here in San Francisco, California? I am looking for a used truck that is preferably not gonna cost me an arm and a leg to pay.
What price? If you mean at least $15 20k then there are lots of Carmax listings in SF and south SF
Just look around on autotempest, cargurus, craigslist, etc. and have a mechanic check it out to make sure the mechanical shape is good. Do this on models proven to be reliable, you could find those in the Used Car FAQ page (at the top of the question list)
Google around the Gilroy/Morgan Hill area. It's about an 1.5 drive south of SF.
They usually have better deals on new cars. I presume used trucks would be down there, because it seems like they use more trucks down there than the city.
+Sunnyvale/San Jose
Rich areas but lots of dealers and usually good prices, Sacramento as well, 100 mile radius should do it