|Gucci Eyewear - $235|
Tilly's has these Full Tilt Rollercoaster Temple sunglasses for $7.97 with 100% UV protection.
Forever21 has this pair shown below for $5.80. Offers 100% UV protection.
Overstock.com has the pair shown below for $10.
I'm always losing my sunglasses so anything under $20 is within my budget!