Woot offers Amazon Essentials Mens Relaxed Fit Lounge PJ Pants 2-Pack for $9.99 (orig. $24.90). Free shipping for Prime Members.

Product Description:
We listen to customer feedback and fine-tune every detail to ensure our clothes are more comfortable, higher quality, and longer lasting—at affordable prices for the whole family. 

• COTTON POPLIN PAJAMA SET: Our pajama sets provide a comfortable and cool night's sleep.
• DETAILS: Button-front shirt with a notch collar and single patch pocket. An elasticated waistband with an adjustable drawcord for ease and comfort, button fly closure, and side pockets to hold your small essentials.
• GENTLE STRETCH COTTON POPLIN: Lightweight and soft cotton poplin with gentle stretch provides ultimate comfort and breathability while sleeping.
• RELAXED FIT: Top: Relaxed fit through the shoulders, chest, and waist. Bottom: Relaxed fit through the hip, thigh, and leg opening. Sits below the natural waist.
• GARMENT MEASUREMENTS: Top Length 28 3/8" from side neck and inseam 9" on US size Medium.