Xixilailai via eBay offers this Rotating Smartphone / GPS Car Mount in Black or White for $1.39 with free shipping. That's tied with our mention from three weeks ago and the lowest total price we could find for any such vent mount by $4 (outside of other eBay sellers). It features an expandable clip that attaches to most air vents.

Note: This ships from Hong Kong and may take up to eight weeks to arrive.