Amazon offers its Amazon Prime members the Natural Crystal Himalayan 8" Salt Lamp
with free shipping
. (Non-members can bag free shipping on orders over $25; otherwise, shipping adds $9.18.) That's the lowest total price we could find by $9, although it was $1 less in August. This lamp purports to work as an air purifier by emitting negative ions and it uses light therapy to reduce stress.
Also available is this Natural Crystal Himalayan Salt 10" Lamp for $30.73. With free shipping, it's another price low, this time by $3.
Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months.