Ok let me put it this way.... I had 1,200 square footage of hardwood in THE most decrepit hardwood I have seen in awhile. Had a company come by and after a lot of head scratching, he came up with a figure right around 2k to sand, prep, stain and seal the floor.
Being a poor college kid, I sacked up, got some buddies together and we rented three floor sanders from menards and went at it. .... if God designated me to live until 80, I knocked off 2 yrs in dust inhalation ( two full size kitchen trash cans full of saw dust), and stain fume inhalation.
All in all its a messy, VERY labor intensive job, but can be accomplished with patience and dedication to save cash. Money wise, the sandpaper pads burn out quite fast and there are three on each machine so I spent a good $100 on those, machine rental was around $150 ish for three machines for 4 hour cracks, stain was 100 bucks, lacquer, brushes, etc etc.... I wanna guess $500 ish total. Only con is you wont feel your arms for days, boogers and lungs are coated with wood particulates, stain fumes will make you hallucinate, but all in all the $1,500 I saved made it all worth it