Careful when price-comparing based on a per-spool quantity, a lot of places seem to be selling half kilogram spools (or 1lb spools in America, which is even less than .5kg) of material. SainSmart is great stuff for the price though, you're on the right track.

Also, any time you can get samples of filament, go for it. Trying out filament brands for yourself is the best way to find what you really like the most.