Walmart offers the Axis 25-Foot Indoor/Outdoor Extension Cord for $7.16. Opt for in-store pickup to dodge the $5.99 shipping charge. That's a buck under last week's mention and the lowest price we could find by $2. It features a lighted power-on indicator and is grounded for 3-wire outlets.
Northern Tool offers the Tasco Multipurpose 1-Foot 14/3 STW Cord Lock Adapter in Yellow/Black for $10. Choose in-store pickup to avoid the $5.99 shipping fee. That's $15 off list and the lowest price we could find. It can be used to secure power cords together.