The increase of people buying on installment or credit in the 1920s is an example of?

I'm not sure if this is the answer, but I believe this is consumer installment, or called consumer credit.

The case was a u.s. supreme court decision that defined the scope of the u.s. congress's legislative power and how it relates to the powers of american state legislatures. the dispute in mcculloch involved the legality of the national bank and a tax that the state of maryland imposed on it.