I got my left handed shears from amazon. They are a brand called "jason" and I love them. About $30 a shear, they're the cheapest lefties I found that still had good reviews from professional groomers.
I have been using them for almost a year now and they've held up through dropping and sharpening. They're cheap enough that I don't have to worry too bad if I've dropped them (I'm clumsy and a tornado in the salon, it's not uncommon) as they can be easily replaced. Yet they are still reliable enough that I've opted to get them sharpened for about half the price it took to buy them lol.
I have the thinners, chunkers, straights, and curves (I LOVE my curves)