Woot offers MAXXHAUL 50016 20-Pack Oval Reflectors 10 Red - 10 Amber Self Adhesive Or Drill Mount - DOT, 20 Pack for $6.99 free shipping with Prime. 

Product Description:
Our MaxxHaul Reflectors provide instant visibility to your vehicles, trailers, RV's, campers and hitch mount accessories such as cargo carriers, bike racks and more up to 100 ft. away. Includes mounting holes for drilled on installation or use self-adhesive backing for quick and easy installation on any flat surface. Overall size of each reflector: 4-3/8" x 2" oval. Kit comes with 10 amber, 10 red reflectors. DOT compliant.

• Provides instant visibility to your vehicles, trailers, trucks, RV's, campers, hitch mount accessories such as bike racks, cargo carriers and more up to 100 ft. away
• Includes mounting holes for drill-on or use self adhesive backing for quick and easy installation on any flat surface
• Overall size of each reflector 4-3/8" x 2" x 1/4" thick oval
• Kit comes with 10 amber and 10 red reflectors
• DOT compliant
• Fit type: Universal Fit