Then, talk to a store manager and ask for a discount. You should easily get one, since the lumber they can't sell gets junked, anyway. You can also get great deals on roll-ends for carpet and linoleum, as well as off-cut wood and other materials. Floor models are also great ...
Buy the cheapest and get more. Stop and think before you buy. Visualize what you will do with it and how many times you will have to dust it. Buy a small starter home and add on later as the family grows. Sell and buy a slightly larger one as the family expands and your career ...