Don't fool with Radio Shack - you will have more money and confusion tied up in one spot quicker than you can figure it out.
Buy them off of eBay from this guy. I have made several purchases with him, and they are excellent quality. Most of his Buy It Now auctions even come with the resistors for 12v applications. And I dare you to compare the prices to Radio Shack.
LED's aren't that bad. Just use a resistor, and solder your connections. And remember, they are polar (+/-) sensitive.