One way is to buy barn siding from a used lumber dealer. Have it edge sawn and routed to tongue and groove it. Be sure that they have run it through a kiln for a couple of days at 140 degrees to kill any bugs. You could do this yourself, but it is MUCH safer to have someone do it. In any case, don't skip the heating. Depending on the wood you choose, have it planed on one side only to get one, good flat side and even thickness across the material.
Move the siding into your house and let it set stacked on 3/4" stickers for 4-6 weeks to equalize the moisture content with your homes environment. This requires a $200 meter to do right, but if you choose to do this yourself, don't skimp on the time and be sure that the wood is stacked where it will be used or close to it.
Lay the floor, edge nailing the tongue edge only. If you have kids and dogs, you might want to lightly sand or use a floor buffet with an old used screen to get the worst of the splinters. Sweep and vacuum the dust! Apply one coat of water based poly that is a matte finish and be sure that you keep the flattening agent--Fuller's earth, talc, or similar--in suspension by stirring the poly often.
Depending on your personal situation, you may want to either take out a new home loan to finance this or pay the doctor and hospital for your fainting spell when you just figure what it will cost. If you have yourown barn to tear down, this will help the cost a little.
You might also want to get a good kit to get out splinters and keep it handy. You could try one board in a wide belt sander and just kiss the surface. Old wood like this is really variable so there is not just one solution to making it both look it's best AND make it reasonably usable.
Your boards will move in relation to the humidity in your house and this changes with the season in many cases. You may have some gapping between the boards in the winter but the tongue and groove joint will keep the boards together and prevent air movement with some underlayment situations
A lot of things are shown in magazines that aren't real practical, but they look great. Designers get a cut of the cost from somebody, in most cases.