In reply to littlejon86:
Get any cheap single rope; for indoor use you don't need dry treatment. Typical manufacturers are Beal, Mammut, Edelrid etc; typical diameter around 10mm? (thinner ropes will normally wear out quickly, and if you are indoors you probably don't care about the weight saving...)
That said I would get a 60m rope in case you ever go outside (plus you can chop 5m off either end when the ends get skanky and still have a 50m rope).
Post edited at 11:03