We like to save money by grooming our dog's hair ourselves. It takes us a couple of hours every three months. Scissors has proven more successful than a shaver. But it's hard to know how much to spend on a pair of scissors. We've gone through a couple of pairs of cheap ones (around $20) and find that they go blunt after five or six usages. What sort of price range should I be looking at if I want scissors to last for at least 5 years or more?
If you'd like a pair of scissors to last 5 years you should be prepared to commit to caring, sharpening, and cleaning them properly. You'll be largely looking at stainless steel - there are newer, shinier alloys and such being marketed but stainless steel is solid and what most groomers/breeders (at least the ones I know) will recommend. Also, the type of scissors you buy should be recommended for your dogs specific coat type (a bichon will require different equipment than a St. Bernard and so on). You can spend $20 and, with proper care, have a pair of scissors last a year or more - alternatively you could spend $250+ and without that same level of care have those scissors be basically garbage in 6 months. With that said you're likely looking at ~$100 per pair.
You might consider having your cheap scissors sharpened professionally - this would likely extend their life a bit, although professional sharpening and good care will never turn a $20 pair of scissors into a $200 pair.
Here are a few options for more professional grooming scissors.
Chris Christensen Adalynn Series - ~$150 Chris Christensen scissors (and brushes) are well liked among breeders and groomers. The Adalynn series is made with high quality 440C steel, and they offer a lifetime warranty as well as free sharpening for all their scissors and shears. My breeder has had a set of Chris Christensen scissors and shears which have held up over 10 years - he has 10 Keeshonds (long fur, thick double coats) which he grooms himself using the same set of tools.
Kenchii Scorpion 8" Straight Pro Dog Grooming Shear - ~$80 Kenchii is another well regarded manufacturer. Scorpion is their base line, and will work well for most non-professional groomers. A set of their scissors will last years, and they have a decent warranty although they don't offer the sharpening that Chris Christensen does.