Please DO NOT declaw your cat just because it scratches the furniture! If you think declawing is a possible option please read up on it and see what they have to do to declaw a cat. It's horrible. In Australia and a lot of European countries, it's illegal - the United States is very behind the times on this issue.
If your cat is scratching, cover the area they're scratching with double sided tape. They won't touch the double sided tape! But you MUST also provide something to scratch on, otherwise they'll just find something else.
Our new kitty was scratching on our couch when we first got her. We put tape all over the area she was scratching, bought a $15 cardboard scratcher and put it in front of the couch. She loves the scratcher, and was scratching just on that. So we moved the scratcher to a better position, and have now removed the tape, and she hasn't scratched on the couch since - and we've only had her for 2 weeks!
If you have a kitten, trim her claws regularly - all you need to is just cut the tip off. It's also useful to hold her paws, and push her claws out every few days just so she gets used to it.
I think the Soft Paws are an expensive option - try trimming the claws, using tape and finding a scratcher she likes first to save you some money!