My advice for you as a newbie is instead of buying 7, 8 or 9 domains at hand reg (that means buying them from a registrar, like 1-and-1, at $7 bucks), that probably aren't that good... save $69 and try and buy 1 good domain that is expiring at namejet.com, or snapnames.com. Or alternatively, look for undervalued domains at sedo.com.
These domains have been registered by someone before, and for one reason or another they have been left to expire. You can pick them up, if you're the only bidder for $69, or you'll go into a 3 day auction, where the highest bidder wins.
For example today,
biographies.info is available at namejet.com, no one has placed a bid on it yet, and it is appraised at $4,700, with a pagerank of 1.
Or
dna activation.com also today, has an appraisal of $14,000 at estibot, yet it currently only has 1 bidder.
You've got a lot to learn, so put your wallet away for a while, and keep reading the sticky posts here at namepros.
My advice is to save up to buy either a short, memorable, pronounceable .com or a 2 word keyword .com that is commercial in nature.