Heh, the biggest thing is our site is for magicians. You will not find a better price on the internet. We even beat Ebay shops and sellers with our pricing. We offer our products so cheap because we are dedicated to giving back to the magic community.
As for the 'being able to do the trick' part, the biggest advice I can give you is practice before you show anyone. There is nothing more disappointing then learning a trick, practicing for a day, then showing someone and sucking at it. So make sure, if you order a trick, you open it up and practice secretively for a week or two. I don't mean one or two days, I am talking about 2 hours a day for 2-6 weeks. Make it so you can do the trick in your sleep... Then when you unleash it you hit everyone with a solid effect that blows their mind.
I see magicians giving up all the time due to this fact, but it's something that must be practiced a LOT!
Thanks for your enthusiasm and I hope you enjoy the rest we have to offer!