aSavings offers the Vivitar Smartphone Selfie Wand with Wireless Shutter Release in Black or Pink, model no. VIV-TR420, for $6.99 with free shipping. That's $10 off list and the lowest total price we could find. It extends up to 40" and is compatible with most phones.
Of note, the Vivitar Smartphone Selfie Wand with Built-in Shutter Release, model no. VIV-TR-365, is also available for the same price.