Cheap Airsoft Grenade Project

I recently have developed a real interest in Airsoft, and I have kitted up which as you know cost quite allot.

I bought a grenade but for every grenade I buy and you use it, it cost about $10-20 depending on which quality one you have to either replace or "re-load". I want mine to be a max of $1-1.5 to refill

Well I have an Idea to make a cheap and reliable grenade that I want to develop I wont be giving my plans out as i want to first see if it works (Safe enough) and so that people can't steal the idea XD.

Any donation can help to develop this Airsoft BB grenade.

I have plans for other Airsoft equipment as well... I just really want to develop the grenade first I'm hoping to develop it so that it will be about $8-10 per grenade. and it will be re-usable.

Anyone that Donates $25 and more will get a free grenade shipped to them when it has been developed