Almost all the condos in Sunnyvale that have sold under $300,000 in the past year are either on or near a busy street. If you are sensitive to noise but can only spend up to $300,000, the order of preference from least noisy to most noisy are:
518 Ironwood Te #2 (Pebble Creek): N of Old San Francisco Rd between N Fair Oaks and N Wolfe
801 W California Av #A : California is a semi-busy street but is not as busy as most of the other streets on this list. The downside is the reduced car traffic is offset by its being the equivalent of a couple blocks away from Caltrain.
999 W Evelyn Terrace & 1001 E Evelyn Terrace : These units are similar in the amount of noise as W California Ave. However these units on Evelyn Terrace are closer to Evelyn Ave and closer to Caltrain than the W California units.
605 Arcadia Terrace #105 : Many units on Arcadia Terrace are close to Fair Oaks Ave and Hwy 101. However this particular unit is at the corner that is farthest from both Fair Oaks and 101.
715 San Conrado Terrace #2 : Similar to 605 Arcadia Terrace except on the W side of N Fair Oaks. (Closer to Fair Oaks but farther from 101.)
708 San Conrado Terrace #3 : Just N of 715 San Conrado Terrace, so a little close to 101.
705 San Conrado Terrace #3 : Closer to Fair Oaks than 708 and 715.
755/771/787/791 N Fair Oaks Ave : Odd number addresses mean these units are on the W side of N Fair Oaks (Same side as San Conrado but closer to Fair Oaks. Opposite side of Fair Oaks from Arcadia Terrace.)
631 E El Camino Real #202 & 633 E El Camino #201 : On E El Camino just E of RemingtonDr/NFairOaksAve.
621 E El Camino St #203 : Similar but closer to Remington/FairOaks than 631 #202 and 633 #201.
929 E El Camino Real #108C : On El Camino across the street from where E Fremont Ave merges/forks from E El Camino Real. Also just E of Wolfe, so suffers from noise from all 3 sources.
1083/1105/1107/1131/1139 Reed Av (#A-#D) : On Reed Ave, a busy street in its own right, just W of Lawrence, an extremely busy expressway.