Stamp collecting is a free-form hobby.
You can collect stamps from anywhere or you can simply collect stamps from all countries on one topic, for instance, some people collect car stamps, others collect planes trains and bicycles, space missions, U.S. Bicentennial era stamps, every country issued commemoratives to celebrate the U.S.A.'s two hundredth birthday.
There are even several countries that regularly issue Disney character stamps. Flower stamps abound from every country, also animals, birds, dogs, cats and a multitude of things that people put on stamps, even stamp collecting. I have a friend who collects British Royalty stamps from every country influenced by the empire where the sun never sets.
I stopped licking stamps with the Pap Smear commemorative!
There is a variety of stamp dealers that have great catalogs online, which will help with pricing the stamps. If you join their club, you can create your own wish list to plan your purchases. You can buy a ready-made album, or start small with a regular binder and a few pages in which to mount your stamps.
We have compiled a few catalogs to get you started.