Is cluster environment needed in alwayson?

Hi All,

I have a question, can  we built 'Alwayson group' without a cluster environment? 
If we can, what are the disavantages in building it? 
Or
If we can not? Why we can not built in non-cluster environment?

I did some research in google some say we can built in standalone some say we can not, but I do not get the concrete answer. The agenda is we are planning to cut cost for clustering. Please help me to understand it.
Also Suggest me some blogs, books for the same.

Thanks

Best Regards Moug