Am intending to buy cubes onlune but i would like to know which online shops are considerably reliable. I've known about HKNow but are there any othe online shops?

It honestly depends on where you live, if you live outside of the united states I can't help you that much, unless it's canada, because most of the US shops will deliver there. If you're looking for more abstract puzzles like the HKnowstore has, there is CubeDepot. If you're more looking for speed cubes you can use Speedcubing Store, Speed Cube Shop, or IcubeMart. Also, Ebay and Amazon are good place to look for Puzzles.

Dealmaz, puzzleaddictions, both very good customer service.

Just make sure to always (and this goes for any store) pay using something that you can use as middle man should something go wrong.

Meaning: don't pay using western union for instance. Money that is gone stays gone that way.