The stuff from the garden store may be cheaper, but it probably isn't safe for something like clothing that is in contact with your skin--different concentration, different inert ingredients (some of which could be toxic). I'd get something formulated for human consumption. Just a quick spray of Repel Permanone seems to work for me (lots of ticks out here, especially the eastern part of the Columbia Gorge).

I prefer to use gaiters rather than trying to tuck pants into socks (they always seem to pop out) or the rubber band strategy.

Please don't spray your dog with it; use Frontline or K9 Advantix topical treatment (check with your veterinarian). Don't put any kind of repellent on your dog anywhere the dog could possibly reach with his tongue (which is most of the dog!). Since the above two treatments don't kill the ticks until after they've bitten, comb the dog thoroughly and check for attached ticks before putting him in the car. This per my-daughter-the-veterinarian.

Always check yourself and the dog (again) for ticks right after returning home!