Answer

Buying behavior is the decision processes consumers follow when embarking on and entering into buying decisions.  

On the NYU Business Library's Marketing Information page  the following suggested resources include:
eMarketer: Provides data and analysis on e-commerce; Statista: Provides market and consumer data across industries; Mintel: Provides market and demographic reports primarily focused on buyers of consumer products.  

Go to the NYU Business Library's Case Studies  section for useful resources including a link to the following suggested resource: 
WARC: Provides access to marketing and advertising articles, trend reports and case studies