There is a promotion on Windex Multi-Surface products at Target: buy three and get one free. Combine the promotion with three $0.75/1 printable manufacturer coupons, and pay just $1.78 each when you buy four!

Buy Three Get One Free through 4/22

Use three $0.75/1 Windex Multi-Surface product (coupons.com)

Final Price: $1.78 each, when you buy 4