Many newcomers to astronomy ask "where can I buy a good telescope"? The simple answer is anyplace where they specialize in telescope optical equipment. Of course you can also choose to purchase from respected retailers online.
A good telescope is, one that is capable of gathering plenty of light and is likely to set you back in excess of $300.
You can purchase a good scope online from and Amazon as many sellers also have their own retail outlets, just make sure you stay clear of the gimick telescopes often sold by department stores which are little more than toys.
The most important thing to take into consideration when buying a telescope is the size of the primary mirror, the larger the better.
Depending on the price of the scope the lenses and mirrors will inevitably vary in quality. Of course if at this point you are still undecided you could opt to try a pair of astronomy binoculars before making your final decision on a telescope. Binoculars are often underated by budding astronomers as they believe they are not powerful enough.
A reflector telescope from Celestron, Meade, Orion or Skywatcher or one of the other leading manufacturers combined with an equatorial mount would be a great start. Keep in mind the size of the scope and if you have sufficient space to locate it.
The majority of large towns will have their own telescope retail outlet or store. If not, many outlets will also have a mail order service.