Neutrino has guided you to some good basic resources. You should look at your budget and look at your goals before making any purchase. It is VERY easy to waste money buying optical equipment that you will seldom use because it is inappropriate to your goals and/or does not perform to your expectations.
I'm sorry if you already know this, but...
Telescopes do NOT show you nice full-color images of nebulae and galaxies. Your eyes cannot integrate color information like photographic film or CCDs can, so you will see extended objects mainly in shades of monochrome.
Aperture is everything. The larger the aperture (given equal optical performance) the more objects your can see, the brighter they will appear, and the better they will be resolved. If you want to be able to see LOTS of objects, a larger aperture is better than a smaller one. You have to weigh this against the storage space required to keep a big 'scope around and the space required to transport it in a vehicle, if you want to take the telescope to someplace that is darker (less light-polluted) than where you live.
The choice of mount should be appropriate to your goals. A Dobsonian mount is the mount of choice for inexpensive large aperture reflectors. Mounting such large instruments on a German equatorial mount (sufficiently rigid and accurate for photography) is REALLY expensive. Dobsonian mounts are not adequate for deep-sky photography, but they excel in ease-of-use for visual observing. It will be extremely difficult to find a telescope capable of astrophotography in the price range that you mention (under $500) unless you find a really lucky deal on a used scope.
REALLY IMPORTANT >>>>>> Before you spend a dime on a telescope, try to find a local amateur astronomy group and attend at least one or two of their observing sessions. You may find that you want a Dobsonian light-bucket to dredge up the faintest stuff in the sky. You may find that you want a small refractor because you want a compact instrument that gives pretty good views of double stars, planets, etc (not that the larger reflectors cannot do this). You may decide that you want a catadioptric 'scope that combines a relatively large aperture with a short (folded) light path. You will never know what 'scope will suit you best until you have tried a bunch of them. Because of my rural location, I went the "go it alone" route, and bought and sold maybe a dozen telescopes before I got my "dream machine" - a 6" Astro Physics AP refractor. This can be an expensive hobby, so if you're serious, please do a lot of research before shelling out money. By the way, if you seek out an astronomy club and attend an observing session or two, talk to the members and let them know that you are in the market for a 'scope. Most of them will either have a spare scope or one that is rarely used, and they will sell it to finance new eyepieces, etc, or they may know of someone who bought a nice 'scope, then lost interest, and will sell it at a fraction of their purchase price.
Good luck.
