Best CHEAP Food in the South Bay??
In Palo Alto, The Counter (a burger and drink should run under $10) and Med Wraps, both on California Avenue, are excellent. Also Homma's Sushi (just off California, behind Primo Cleaners) and Cho's (for great potstickers).
In Mountain View, Taqueria La Bamba for carnitas burritos (Old Middlefield Way), Kauai Grill (for the Kalbi ribs), Taqueria Los Charros (for cheap, greasy Mexican), Bean Scene (sandwiches, pasties), Gyro's House (Greek), Hong Kong Bakery (passably good dim sum).
In Sunnyvale, Giovanni's for the chicken parmagiana sandwich (the pizza is good, too.)
When I worked in Palo Alto, my fave non-Mexican cheap eats ($5-10) were in Mountain View: Queen House on Castro Street and Pho To Chau on Villa a block from Castro which is kind of divey but an old time favorite of many in that area.
hhc's recent report of Queen House with photos:
There's so many other cheap eats options in the list of cities you gave, it's just hard coming up with the "Best". Below is just a few of the "best" for my tastes.
In Mtn View, Ryowa & Maru Ichi for good ramen for around $10.
wchane's link to the places in/near Santa Clara is very useful. From the mentions in that thread my favorite cheap places are:
-Tong Soon on El Camino & Pomeroy (some things are more than $10 but lots under $10
)-Mayuri's for Indian Buffet (around $8 for lunch)
-St John's Grill, good moist burgers, cheap when they have buy one get one free burgers (Saturdays?)
-Su's Mongolian on El Camino if you want to stuff yourself for decent AYCE mongolian bbq.
-Korea House in Santa Clara has a very cheap AYCE lunch but it's just okay; but lots of reports of great food if you order from the menu
But read that thread, it's really worth reading.
Also, there is Golden Phoenix Supermarket on Rengstorff & Middlefield which makes the only banh mi sandwiches (around $2)that I know of in the 101 corridor of PA/Mtn View/Sunnyvale/Santa Clara), as well as a small decent steam table where $5 gets you a big heavy styro box full of food.
If you are venturing as far North as Palo Alto, $10 will buy you any of a couple different plates at Mediterranean Wraps on California Ave., convenient to both El Camino Real and Central Expressway (Alma Street, this far North). http://www.kanzeman.com/medwraps.htm
I really like their baba ghannoush, and I often order the "combo plate with shawerma" featuring a side of either chicken or lamb/beef.