Walmart offers the Mainstays Blackout Grommet Curtain Panel Panel in eight colors (Grey pictured) with prices starting from $8.97. Opt for in-store pickup to avoid the $5.99 shipping charge. (You can also spend $35 or more to qualify for free shipping.) The sizes:

• 40" x 63" for $8.97 ($2 off)
• 40" x 84" for $9.97 ($2 off)
• 40" x 95" for $10.97 ($3 off)