Friday is a day for green.

Cheryl Cotter knows that, and that’s why she is urging Friends of the Warwick Public Library to “wear green and bring your green.”

Friday is the first of three days of the Friends’ semi-annual book sale that annually raises about $9,000 to support library programs. It’s the time when Friends, who pay $10, get first pick of the hundreds of volumes to be sold. The sale is opened up to the public on Saturday and on Sunday, rather than selling individual books, buyers get a bag and are welcome to stuff as many books into it for a set price of $2.

Cotter, who runs the sale, doesn’t know quite what to expect for the first sale of 2017. The sales are traditionally a success, bringing together people of all ages from kids to senior citizens. Prices have always been impossible to beat at 50 cents for paperbacks and $1 for hardcovers. But that’s changing. Prices have doubled to $1 for paperbacks and $2 for hardcovers. The goal is for the Friends to be able to do even more for the library.

“My feeling is that it’s for a good cause,” said Cotter, adding that she has her “fingers crossed” that people will dig a little deeper into their wallets.

In a very real way, the Friends’ book sale is the community investing in itself.

Library director Christopher LaRoux estimates at least half, and many more, of the books sold have been donated. He said the library receives a steady stream of donated books. They could be coming from estates, people moving away from the area or simply to make room for newer unread books. CDs and DVDs are also given to the library and sold at the sale. The library adds to the for-sale inventory with copies it deems no longer needed for its collection.

LaRoux said people leave off books at the information desk, or if donating collections drop them off in boxes at a library side door.

He’s amazed by what happens next.

“They have this down to a science,” he said of the Friends.

Once at the library, the books are taken to the third floor, where they are sorted by fiction and nonfiction. Also, the donations are examined. Some may be first editions and even rare. These are pulled aside to be sold at higher prices than the universal bargain rates. After being grouped by categories based on topics, they are boxed and then, according to schematic, are displayed on tables in the large meeting room just off the library entrance. There are so many books that they can’t possibly all fit on the tables. Boxes are stowed under the tables that are opened during the sale to replenish the display.

On Saturday morning the room hummed as books by the box were delivered to their designated table. Judy Gorton worked the cookbook table. She’s seen dealers using scanners to read bar codes and pack away volumes to be resold at attractive profits.

That’s part of the sale; you don’t know what you might find.

That doesn’t bother Cotter. Dealers, like all members, get the first pick of the books Friday evening from 6 to 9 p.m. Like everybody else, dealers can become members by paying the $10 dues. Membership will be open during the sale, and Cotter is hopeful of growing the ranks to 500.

“If you are a friend, bring a friend,” she urged.

A membership of 500 would mean $5,000 in membership dues.

“It’s all going to the library,” she reminded.

The Warwick Library is one of the busiest in the state with 400,000 visitors a year. Last year, the library and its branches loaned 572,000 items. In addition, the library saw a 51 percent increase in program participants at a total of 18,000.

LaRoux said the Friends’ contributions help pay for half of programming costs. All library programs are free and open to the public. Registration is requested for special events where seating may be limited or including refreshments and program materials.

The sale kicks off with the Book Sale Preview on Friday, March 17 from 6 to 9 p.m. The Book Sale Preview is free to members of The Friends and $10 for non-members. The Friends of the Library Book Sale runs on Saturday, March 18 from 9 a.m. to 4 p.m. and on Sunday, March 19 from 1 to 4 p.m.