There are some interesting trades in cotton these days, my friend specializes in trading futures, I believe he is partially the reason for the increase in prices as he holds about 40% of open interest on the CBOE.
If you make the SF minimum of 250k/yr, after tax you should have about 150k which is about 12k a month to spend. Here's how you should break it down:
Save as much as you can.
Cash under pillow -> Checking -> Savings -> Retirement -> Investment Vehicles
Generally people recommend 6 months living (including rent) that you keep liquid (more liquid than savings)