Walmart offers the Stanley Folding Utility Knife for $4.99. Opt for in-store pickup to avoid the $5.99 shipping charge. Excluding the below mention, that's the lowest price we could find by $4. It features a quick-change fixed blade, 1-handed open/close, and stainless steel belt clip.

Note: With orders of $25 or more, Amazon offers it for $4.84 with free shipping. (This item is part of Amazon's "add-on" program and can only be purchased with an order of $25 or more.)

Update: The price has dropped to $3.99.