Sears offers the Southpole Men's 4180 Relaxed Fit Jeans in six colors (Dark Blue pictured) for $18.99. Choose in-store pickup to avoid the $5.75 shipping fee. Outside of the price below, that's the lowest total price we could find by $4. They're available in waist sizes from 29 to 42 and lengths from 30 to 34, although not in all size/color combinations.
Of note, Shop Your Way Rewards members will earn a Sears credit with this purchase and may be eligible for additional credits and discounts. Plus, Shop Your Way Max members are eligible for free shipping.
A close price, Amazon offers the jeans in a various styles for $20 with free shipping for Prime members.