well, i havent gone into looking into making my own kit, but i can almost promise you it wont be cheaper. when you buy a full kit they cut you a break on the prices VS if you went out and bought it seperately. thats what a kit is...everything together for cheaper than buying seperate. if you wanna go cheap buy a used kit. i paid 430 shipped for mine...barely even used, and came with a purge and gauge as well as all the rest of the parts. have you even looked at the price of solenoids? they are like 150-200 EACH. not to mention a bottle which is about the same. and you dont have any switches, brackets, relays, hoses, control box (if applicable), nozels, jets. so just with 1 solenoid (say your using a dry system) and a bottle, your already up to $300-400 and your nowhere even close to ready.