Bonds and their price fluctuations

Im having a hard time grasping why bonds fluctuate in price. I understand it probably has to do with the bonds exchanging hands and interest rates but can someone please elaborate? Also how where can I buy or see US bonds for sale like I can with stocks on an online platform. Also whenever corporations offer bonds where do I go to buy/see these?

You can buy bonds in your Scottrade.

Face value of the bond stays the same, but the fluctuation in actual bond price on the open market effects the interest rate you're getting depending on what you buy it at.

You may want to read this:

http://www.investopedia.com/university/bonds/bonds3.asp

Also, since you have Scottrade you probably have a local rep you can call that will help you out with this stuff rather than waiting hours for someone here to respond. I'm always willing to answer questions, but in your case a phone call to the local broker may better suit you and speed up your learning curve.