This bike teardrop has everything we want in a trailer: it’s lightweight, cheap, and 100-percent DIY.
Just buy the $45 blueprints from Wooden Widget, gather the necessary materials (mostly wood and PVC), and start building. Wooden Widget says the whole process should take about 50 hours, and while it doesn't offer a total cost estimate, it suggests using recycled wood to keep the price low.
Once everything's put together, riders will have a 65-pound trailer that folds down to two feet wide when it’s being towed and expands to a little over three feet wide (just enough room for two people who like to cuddle) when it's time to hit the sack. If you're hauling the unit in a car, you can collapse it down to eight inches tall.