Would white or off-white drop clothes be good to use as furniture covers?

i saw it in a magazine once...said they were cheaper that the fitted furniture covers...How much do drop cloths cost anyway?

What a cool idea my daughter did and they looked great a goob drop sheet dose,nt cost much, I,ve had drop sheets for years and wash them after evey painting job I do , you can get them in many sizes, Your on the right track ,and the look is great too, Good Luck watch your fingers on that sewing mach.LOL P/S a good drop sheet is not expencive 20-30$$

Prices can vary wildly. The thickness and coatings are most often the factors. Drop cloths are quite rough, but I have seen that idea also. I would think they are too rough, but could be quite water resistant if you get the right kind. I don't think they would be much cheaper, though, because of the standard sizes they come in, you would waste a lot of fabric. Maybe for a couch...

I don't really know...I have an inexpensive quilt on my futon.

I am assuming you mean like painter's drop cloths which are usually somewhat clear. They are inexpensive in a dollar store about $2. The white and off white, would get soiled easily. I assume you just want to protect your furniture......so use the cheap drop clothes in a thick mil so they won't slide off as easily. They still sell the cork screw type of fasteners to hold it in place. A fabric store may carry them or a hardware store. If the mil of the plastic is think enough, it should hold providing there's no rough-housing on it.
You can buy remants of fabric that would look better but will cost more but not as much as furniture covers. Use the same fasteners as I mentioned above to hold that in place. How about more than one plastic tablecloths which are also sold in dollar stores? You can glue two or more together. Be creative!