beans, $700 / metric ton [1]
rice, $500 / metric ton [2]
a meal of 65g dry rice and 55g dry beans per person.
700m * 3 = 2.1b meals per day
115,500 tons beans = $80.9m
136,500 tons rice = $68.3m
Total $149.1m/day
I'm sure at these quantities you can get much better prices of rice and beans, even just browsing on alibaba. I'd guess we can probably get that down under $100m from alibaba. Probably even lower at the quantities we're talking about.