I am a crystal dealer and have been in the business for over a decade.
While i usually take advantage to post links to my main site, i will refrain and try to give you the good oil.
Selene is correct in that ebay is your best bet in terms of variety and value.
I assume you are looking for natural unpolished crystals for use in orgone devices, or for other metaphysical uses?
What you should try to aim for is to pay no more than US$100 per kilo to get them to your door for crystals smaller than two inch, US$130 per kilo for the longer ones.
The two sites linked above, frankly are rip offs IMO. They do not give weights, even for their "wholesale" offers, and in a rough estimate i figure you will be paying US$300 - $500 per kilo at those sites. And the lack of detailed pictures for those lots mean you may well end up with C grade rubbish.
I just had a quick check on ebay. There is heaps of bargains there as I type. One guy is selling 2 pound lots of nice looking 1 - 2 inch crystals (nice form / good mix of single and double terminated) for US$16.50 + 35.00 shipping worldwide. That works out to about $60 per kilo to delivered to your door.
Even i can't beat that
Work out the total cost by kilo (price + shipping divided by weight) and aim for $50 - $100 kilo delivered to your door.
Look at the detailed pics - if none are supplied then forget it. If the weights are not given then forget that too. And check the seller's reputation - if he has over 150 ratings at 98% or more, then he/she is probably a good bet.
That's my advice if looking for natural crystal. Avoid commercial crystal websites - get your bargains from ebay.
P.S Use the Key words "Quartz Crystal Point" in the ebay.com search bar to get the best results. You will have a lot more pages to go through, but you won't miss anything that way.