1) Bargainer 2) Bibliopolist 3) Dealer 4) Monger 5) Trader 1) Bibliopolist 2) Bookseller 
• (n.) One who sells books.
Bib'li·o·pole noun [ Latin bibliopola , Greek ... ; ... book + ... to sell: confer French bibliopole .] One who sells books. 
A bibliopole is a dealer in rare books.
[n] - a dealer in secondhand books (especially rare or curious books)
bibliopole A dealer of books, a bookseller; especially one who deals in secondhand and rare books.
bibliopolist noun a dealer in secondhand books (especially rare or curious books)
a bookseller, esp. a dealer in rare or used books.