how would i go about doing a incubator i would love to have one but ant got the money to buy a store bought one
You need to answer this question to yourself, "How many eggs am I going to incubate?"
If you are incubating 20-30, a cooler incubator should do you quite well.
If it is more 50, you may want to thing pretty big, You could still incubate in a cooler with 50 eggs, but the cooler would have to be Really big.
If it is more than 50, you will want to make a cabinet style incubator.