Please do not go to notary public for help in your deferred action application. As mentioned by other colleagues, it is illegal for them to practice law without a license.
I strongly advise you going to consult an attorney to go over your application. I have done quite a number of deferred action applications in the past few months. I can say that although the application form is simple to fill up, the supporting documents that need to go with it could be crucial to the success of your application. Your documents should show that you have met all the requirements of the law.
You certainly can shop around for an affordable attorney. If your case is not a complicated case, such as you had violated some laws in the past, you may go to some non-profit legal aid foundations for help. However, if your case is a complicated one, you need an experienced attorney to deal with it. Most non-profit legal aid foundations will not deal with complicated cases.