Remodeling is time consuming and usually pretty expensive. You'll probably want to use a contractor for major work like moving walls or adding a second story.
If you want to minimize your overall remodeling expense, click lock flooring is a great opportunity.
Since flooring contractors typically charge $2-$3 SF for installation and with many click lock floors in the $3 SF range, this translates to a savings of around 50% when you DIY.