I dont think I have ever bought online... I have aquired several at various events and local stores (I have to hold them) though the very best way, IMO, is to dig them yourself Are there any dig sites near where you are at?
I've bought several palmstones and a few tumbled stones from this seller in the UK: http://www.thecrystalcaveshop.co.uk/
I'm in the US, but the prices are so good and the shipping is so reasonable that I prefer to buy from them. They ship quickly and everything I've gotten from them I've been pleased with.
They also have an Ebay shop (US); I believe the seller's name is domtomrac.
5 Large Blue Chalcedony + Quartz
5 L (for Large) Snowflake Obsidian + Quartz
5 L Banded Amethyst + 1 Large Quartz
5 Large Ocean Jasper + 1 Large Quartz
I bought Apache Tears from a seller called bluewatercrystals. Also Chrysocolla, Lapis Lazuli, and Magnesite which he sent as a gift!
There is this website called Krystal Love that looks very good-I haven't shopped there though because I have a shop near that has everything I need (so far! ) but thats where I would go If I needed to get crystals online.