VMInnovations offers the Xec-Fit Adjustable Height-Convertible Sit-to-Stand Desk Riser for $101.99. Coupon code "DealNews5Off" cuts it to $96.89. With free shipping, that's the lowest price we could find by $3. It rises from 5.9" to 17.9" and features dual gas springs, a 32 x 20.7" desktop, and sliding keyboard tray.
If you have or expect to have a modest retirement income, you may want to avoid spending your golden years here.