http://sporestore.com/section.php?xSec=3 The Spore Store has got some nice cubensis variety-syringes at 10$ a pop. My advice: grow PF-tek. Its easiest and probably the only way your gonna have some sucess with it as a first time grower. Also do a lot of research (check out the Shroomery) and just make sure you know the process like the back of your hand before you try it. You should be alright so long as you do your research and follow the guides.
I prefer spores101.com. It took maybe three days for my friend's syringes to arrive, and they sent him two when he only ordered one. Also, B+ seems to be the most popular strain for beginners.
strains are mostly B.S., though some varieties DO have some relatively consistant differences. all in all they're mostly the same in terms of potency and effect - it mostly just depends on how they're grown. strains with a reputation of being fast to colonize, such as cambodia, are a decent bet. fwiw i've heard people say often that PRs will render some particularly potent mushrooms, but like i said in my experience claims of differing potency are mostly bullshit and its all dependant on how theyre grown. and yeah, the PF tek is the best bet for a newby. google "PF Tek for Simple Minds" and you'll find a great, simplified, illustrated guide.