Amazon offers the Allen Sports Ultra Compact Folding 2-Bike Trunk Mount Rack for $29.92.
Ultra-compact 1-bike carrier for traveling and commuting
Folds up small and fits inside carrying bag or backpack
3 padded legs rest against vehicle; 3 adjustable security straps
Tie-downs and padding keep bike secure and separate from vehicle
Fits sedans, hatchbacks, minivans, and SUVs