Derived from the cheap generic products you can purchase from the supermarket home brand can be used as an adjective. If something or someone is home brand it may be cheap, lame or distasteful. When used in this context it generally has negative connotations.
"That guy is such a home brand"
The cheap ass 2 dollar brand found at supermarkets that taste bad but people continue to buy becuase its 50 cents cheaper than the good brand.
I just made my own coke with all Home Brand ingredients. It tasted worse that Home Brand cola.