It's expensive and the chair should be worth it.

Depending on the design of the chair and how difficult it might be to reupholster, the labor will be between $300 and $600. (And you get what you pay for, in this field.)

New fabric will run between $20 and $60/yd, and an average upholstered chair will take about 7 yards.

Most folks buy new, unless we're talking heirloom quality furniture or high in sentimental value.

(You might want to consider ready-made slip covers in a neutral colour with a throw pillow or two for an accent.)

If you can go to a fabric shop and pick out your own upholstery fabric (if you trust your judgement in doing it yourself) instead of buying from the upholsterer you can save a bit of money, since they're marking up the fabric as the go-between. Also, some upholsterers will not just remove and replace fabric - many routinely taking the piece down to the frame by removing all the padding and stuffing inside and then rebuilding, even if a piece is only a few years old and doesn't need it. So your least expensive bet is to buy your own fabric and then find an upholsterer who will only remove the old fabric and replace it with the new without messing with the innards of the chair. If the chair is older (like, ten years or more), they're probably going to pretty much insist on new padding.

Depending on the chair, it may be worth it to do it yourself. My mother and I have reupholstered several chairs. There are lots of guides on-line.

Alternately, Specklet's slip-cover idea is nice.

A decent upholsterer should return an even better piece of furniture than when it was new.

An indecent upholsterer. . . .well I'd rather not get anything back from them.

My mother has done it on several chairs which I only just realized that she's had for more than 40 years. They're classics, and very well made pieces of furniture so in those cases it's totally worth it even if it is expensive. She went from crazy wild seventies pattern to a nice neutral sand on one of them and is now saving up for a sexy gold damask with a dragon pattern on it (since she's moved and neeeds to re-match things in her living room).

Her last upholsterer was in the states, and he actually simply put the new fabric on the old which wasn't expensive at all. This time he will probably need to strip and restuff which is why she's saving up for it, plus the fabric we want is teh pricey.

I've done it (badly) on smaller chairs that were fleamarket finds. It takes some time but can be done depending on the chair. I'd never do it on chairs like moms.

I've reupholstered furniture. To date I've done a wing chair with a matching hassock, and a buttoned tub chair. It's a lot of work, but it's not rocket science. Basically you just just take it apart and use the old pieces as a pattern for the new ones, then put it back together the same way. You'll need a sewing machine, a staple gun, and a screwdriver (for taking out old staples). If you have to replace padding, you'll have to have that. And of course, baic knowledge of how to use a sewing machine, and lots of time. I estimate it took me 30 hours to do my buttoned tub chair. But it was worth it. A $15 thrift shop chair with very seventies worn corduroy upholstery (I found a 1978 penny in it) is now a paisely chenille upholstered chair that looks brand new.

If you have to do buttons, take a few sample old ones to an upholsterer with a length of your fabric and they'll cover them for you quite cheaply - I think I paid 10 cents a piece the time I had that done.