Salifert is a high quality test kits that can also be used for fresh water. So I would just use them if you already have them laying around. That is if they are the ones you need for testing your planted tanks.
I use a combo of Tetra and Aquarium Pharmaceuticals.
I usually see the Tetra master kit for $21 and the AP kit for $28, but the Tetra kit doesn't include NO3, which usually adds another $10 or so. I don't really like the AP NO3, though, so.. I guess I'm just strange!