For years, Amazon has been eating indie bookstores’ lunch with its vast selection; discounted prices; and, more recently, free shipping for “Prime” members.

So it’s always interesting to see how some savvy booksellers are trying to stay in the game. The latest example comes from Politics & Prose, the storied bookstore in Northwest Washington.

Joan Dawkins, left, and writer Kay Jamison peruse books at Politics and Prose in D.C. (Katherine Frey/The Post)

New branded shipping boxes unveiled on Memorial Day Weekend at Politics & Prose Bookstore in Washington.

Over this Memorial Day weekend, P&P is offering free shipping for online orders over $75. Director of marketing Lacey Dunham notes that this “is first time we’ve offered free shipping through a web-only promotion.”

The store is also introducing a new shipping box branded with its logo. “As far as boxes go, they’re snazzy,” says Dunham.

But even this aggressive offer illustrates just what a formidable competitor Amazon is.

Amazon’s Prime membership costs $79 a year and provides free two-day shipping on essentially any purchase; P&P’s special Memorial Day offer includes free 4-7 day shipping but only for much larger purchases.

Dunham says, “We’re experimenting with different online promotion options. We recently ran a one-day 30 percent [sale] on all online orders. D.C.’s population is transient, and we’ve found many folks fall in love with us before moving elsewhere without a local independent bookstore, and we want to extend our online presence to those who live outside the D.C. metro area.”

P&P does not charge sales tax on orders mailed outside of D.C. Amazon currently charges sales tax on orders shipped to nine states.

And so the battle for book buyers rages on.