I’m assuming you’re in Canada? There aren’t a lot of choices as far as switches that will work with LEDs and don’t require a neutral other than the Lutron Caseta, and while those are very good switches, they may be out of your price range.
Of course if you only get smart bulbs, you might be able to get away with battery operated switches, and then you do have quite a few choices. See the following thread:
There is one brand new zwave device which is battery operated and fits over your regular switches and turns them on and off. It seems to work well, but the problem is the batteries only last for a month or two, which may not make them a good choice for regular use. And it cost $40 US. So I personally would choose the Lutron instead of these, but it is another option.
As far as knowing which devices will work with SmartThings, see the following FAQ: