They usually cost you less:
Solano County sales tax is lower than Sacramento, Yolo or Contra Costa counties
No gas or auto wear-and-tear costs or bridge tolls
No shipping charges! (Read those Amazon ads carefully; a book that costs 1¢ plus $3.99 shipping is not a 1¢ purchase, and different sellers don’t combine shipping—three 1¢ books can cost $12, not $4.02)
Your purchases benefit Rio Vista:
Part of the sales tax paid in Rio Vista is income directly to the City of Rio Vista
Another part of any sales tax paid in Solano County supports Rio Vista through County services and expenditures
Purchases from Friends of the Library and Books Rio V support local libraries
Any purchases made in Rio Vista help keep our community economically viable
And Finally:
You can examine the books at your leisure to be sure they suit your purposes, and sometimes get reviews from people you know!