autohosted apps for hosting cast by microsoft

Question

Hii to all ,

I want to know about autohosted apps deployment in windows azure hosting. What is the cast provide by microsoft for using autohosted apps. I have done one autohosted apps and i stored that apps in sharepoint store. If any body use that apps than some charge is applied by microsoft for deploying that apps in windows azure or free..? i am confuse about that...please help me...