Cutting corners may seem like a good way to save money at first glance. Certainly there are plenty of ways to cut corners effectively. Go to yard sales and thrift shops to buy linens and buy linen dish towels to make curtains etc.. Pre cut so no sewing, spring loaded rods...very easy and cheap.
Old linens that have no special appeal because of antique value can just be worn out cloth...this means you will buy over and over again.
Just an example that came to mind.
When you build, do not build with the first and cheapest materials that come to mind. If you find a lot of boards free on craigslist for instance, they may look like your wall sheathing...a real gift...but in time those boards will not give you the diagonal stability you need. You will never be able to use sheet rock if you do not have that stability. You can, of course, run sheet metal diagonals in your walls under the boards, but there is another expense and time. Just bite the bullet, and use plywood or some other sheet product and do the job right the first time.
Deke Diedrickson has a lot of great shelters built with salvaged materials and corrugated translucent panels, but you simply cannot have quite that mindset with a permanent building. Buy windows that are not all worn out, or be choosy when recycled materials are offered.....why be in the position of having to redo your work. If you come across a nice stained glass panel....that is a different story.
This sometimes means that construction will not be as fast as you would like. Saving up for materials takes some time. Finding just the right salvage will take more time.
You need to be patient and critical of bargains. Think long and hard about purchases and construction methods. It does not always help to be too quick and too cheap.