Walmart offers the Haitral Portable Sewing Machine for $17.99. Opt for in-store pickup to dodge the $5.99 shipping fee. (Amazon charges the same.) That's the lowest price we could find by about $3. It features two speeds and a foot pedal. Four AA batteries are required but not included.

Update: It's no longer available for pickup at Walmart; however, Amazon still offers it for $17.99 with free shipping for Prime members.