Reusing Plastic
Here yet another gardening hack that you should give a try. If you don’t want to spend money on seed trays, just use whatever plastic container you have at home. Use a cheap soldering iron to melt holes into the bottom to allow excess water to drain, then pop a few seeds into the container. Voila, you now have a seed tray without going to your local nursery store.
This person used an old plastic egg carton as a makeshift seed tray. The ingenious thing is that they could plant multiple seeds and move the seedlings to bigger pots later on.