1069: air tickets headache

i'm trying to source for the best price for tix to US. to decide whether i can afford to go. i think i can.. but its a little steep still. which is the cheapest state to land from SG to ? i think it's san francisco, but i actually found tix to LA at S$960 b4 taxes. I haven't book any tours/ flights etc from Sg b4, so abit unsure to where got best deals.. any help? i'm hoping for Open Jaw tix actually, want to go in August, for bout 20 days i think, and i wanna go LA, Las Vegas, New York and San Francisco. hmm 5days per area should be good enuff, but i need to buy the tix to go there first. hah.