Getting commodity prices android

Good morning,

I want to do an android native app using java that can get and display cotation of agricultural commodities like corn, soy and living cattle. The problem is that I've never worked with others database, and I don't know how to do it.

I've already had a lot of research but I've only got confused because people say to not use yahoo finance, then people say to use it. Long story short I don't know exactly how to do it or what api I should use if I should use and I'm needing someone to guide me on how to do it or just specify what I should been searching for.

There's anyone here that could help me?

thanks