I took a look at the two graphs.

I would prefer the price of onions - seems like the price is a lot more stable other than a few points out of the year where it is very high. For those times, I could choose to have a small store of onions or go without.

For the price of corn, if the price is high, chances are it will be high for a while, so I'll have to go without for a while...

What do other people think?