a 1,000 square foot basement, could very well end up needing 3-4,000 square feet of drywall! depending on walls built, soffits needed for ductwork and piping.?
if you're building walls? I suggest you get your first line chalked in red. and square every other wall off that line, by pulling 3-4-5 or any variable thereof? 6-8-10, 9-12-15 and so on in feet. find your corner point on first line, put a pencil mark out 3 feet, then from your red chalk line, go out 4 feet the other direction making an arched line with your pencil, keep it exactly 4 feet through the arch. the distance from to 3 foot mark diagnaly to the 4 feet mark should be exactly 5 feet. the largest 3-4-5 variable you can use will be most accurate. after lines are chalked, I like to take my framing square to double check squareness, and put a good heavy pencil mark for corners, and paint them using construction ain't just heavy enough to let the pencil marks still show through! the way the marks will always be there if need re chalked after sweeping floor. use a plumb bob to transfer floor lines onto ceiling joists, to make sure top marks are plumb with floor marks so ceiling will also be square. once all partition marks are chalked, you can measure exact measurements from square lines to mark other partitions and all should be square.
once allpartitions have been built, read my post on the recommend good book, I typed the how to do drywall in pretty precise detail on how to both hang and finish drywall.
figure up total sheets of drywall needed? have it delivered, but drywall hammers, find helper and get to work. don't forget finishing tools mud and tape.
contactor cost= nothing/zilch! your costs= materials and some labor at your own speed and pace!
sand, buy paint , pans and rollers/brushes and spend a day with the mrs.!
done!!