We sanded the floor in one of our front rooms ~ very hard work. One sander is not enough as you also have to hire the edge sander or you won't be able to match the .... errrrr..... edges. The hire shop charges for both and also sells you the sander belts and discs. The mess is incredible and at the end of the day I was pushed to finish the job before the hire shop shut so had to pay for a second half day's hire.
A "professional" (See yellow pages) would have cost £300 and that was to strip the floor, clean up and then stain and polish the floor.
By the time we had finished "saving money" we had spent two days doing the job, both had aching backs and Mrs S#2's asthma was bad for a week because of the dust from the sanding. And I saved? £50 which was then spent on buying stain, varnish etc to achieve the colour Mrs S#2 wanted.
Honestly Nick it is not worth the candle. Get a man in. You will get a professional job done, all mess cleared and Mrs Nick will be happier in the end.
Mrs S#2 is still not happy (two years on) with the finish we managed doing it ourselves and we are still finding sawdust!!