What telescope should I buy for myself or my child?

I saw a 600-power telescope at a local department store. Is that a good deal?

How much do I have to spend on a beginner’s telescope to have a really usable instrument?

Can I build my own telescope?

Do I need a telescope to see things in the sky?

After the moon and bright planets, I can’t find anything else in my telescope. Why?

What is the “best” telescope?

I am putting up a security light. Will that hurt my views of the sky?

What is the best eyepiece for my telescope?

Can I take photographs of things in the sky?

I'm an absolute beginner, can you give me a quick primer on astronomy and telescopes?