Metro man, going by the posts on another forum, you are a little high on your estimates.
SG$700-850 is being quoted as basic monthly for Jetstar, so you would have to do a lot of selling to get to $2000 from that.
Singapore expats forum
DrPepz, SQ crew would be lucky to take home SG$5000 per month including allowances and most are probably on SG$3500-4000.
(and are working their rings off)