Designer Living offers the Madison Park Soria 50" x 84" Rod Pocket Panel Curtain
in Striped Linen (pictured) for $13.99
for shipping. (The discount should be applied automatically, if not, you may have to apply coupon code "MDAYMP30" during checkout.) That's $11 off list and the lowest total price we could find. This polyester blend curtain is machine washable and fits a 1.5" diameter rod.
Of note, also available is the 50" x 108" curtain for $17.49 plus $5.95 for shipping. That's $13 off and another price low.