How can I get my stubborn immature thick headed know it all husband to listen to me when I put my 2 cents in?

Ok.. I'm 33, was raised by a single mom and was a single mom forever. I know how to fix things around the house. I know how to do probably his job and my job, equally if not better then him. He is 27 and the age difference can make us but heads. Anyway, since we moved in our new home, there are some things that are needed to be done around the house. So, whenever anything needs to be "done", he usually goes above the necessary means and makes things "harder" then what they need to be. And ends up spending way too much money, in my opinion is a waste. So, I will put in my 2 cents, usually its a simpler and cheaper way of doing it, but not a short rigging it cut. He just says no, with this, cynical laugh, and says we are doing it this way. So I get so pissed off, because he makes me feel like I am extremely dumb little girl who knows nothing. I have asked him not to act that way towards me. Whether he is right or not. He has gotten way worse, since he became a manager at his new job. GRRR I can't deal with it. It makes me so upset and hurt, that I don't like him.. and refuse to help him. I don't get it, is it a man thing? An immature man thing? Or just him and his lack of respect for me as a wife? And how can I make him stop that, cynical you know nothing laugh and always doing it his way?