There's always the

cheap-jack, n

1. a person who sells cheap and shoddy goods.

The noun borrows a connotation from a sense of the adjective:

3. unscrupulous or underhanded

(cheap-jack. (n.d.) Random House Kernerman Webster’s College Dictionary. (2010). Retrieved November 27 2015 from http://www.thefreedictionary.com/cheap-jack).

There's always the

cheap-jack, n

1. a person who sells cheap and shoddy goods.

The noun borrows a connotation from a sense of the adjective:

3. unscrupulous or underhanded

(cheap-jack. (n.d.) Random House Kernerman Webster’s College Dictionary. (2010). Retrieved November 27 2015 from http://www.thefreedictionary.com/cheap-jack).

Merriam-Webster defines 'cheapjack' with exactly your term:

1 : a haggling huckster