You don't necessarily have to spend so much in customising your airsoft guns. In this video USAirsoft has a list of the top 10 cheapest custom guns that you can consider... "I get asked to do more budget friendly countdowns so for this episode of The Airsoft Tops Series, we'll be taking a look at just 10 of the cheapest custom airsoft builds that are spread all around the world to prove that with just a little creativity, imagination, and craftiness, you too can make something special for as low as zero dollars."