In this video I tested the difference between the SOG folding saw, the Silky Gomboy folding saw and the Ozark Trail folding saw (purchased from Walmart.) I wasn't surprised with the results, and you really do get what you pay for.
The Walmart folding saw was $10 (and was horrible)
The SOG is around $20 (not bad for the price)
and the Silky 210 folding saw was $40 (a good buy)