The old rule of thumb that I used was a reasonable price for a cruise was $100 a day per person, but the bad economy has caused the cruise lines to offer many deals at lower prices.
Being mildly claustrophobic I don't book inside cabins. I've had balconies on many cruises but have come to regard it as undesirable. When underway it is usually windblown and uncomfortable. When in port you go ashore for local color and by the time you return the ship is getting underway again, so use of the balcony is limited. Also, without a balcony you get a larger cabin with an oceanview.
I've sailed on the megaships on on the medium sized older ones. Both have virtues. Megaships cannot use the Port of Tampa due to having to sail under the Sunshine Skyway Bridge.
If you sail out of Port Canaveral the itineraries are mostly the western Caribbean with stops in Mexico. As a matter of principal I am no longer willing to go to Mexico. There may be a couple of sailings that go to Key West and Jamaica, I haven't checked lately.
I strongly recommend sailing the Eastern Caribbean, which may mean sailing out of Miami or Ft. Lauderdale.
HERE IS THE BEST TIP I CAN GIVE YOU: There are motels in Port Canaveral and Ft. Lauderdale where you can stay the night before your sailing that will provide you with free parking for the week of your trip and free transportation to and from the port on the day of sailing.
Although you could drive to either port on the day of the sailing, I have experienced arrival anxiety when doing that. What if my car breaks down; what if I'm in a traffic crash; etc. And......... the parking fees at the port can be quite expensive and must be paid in advance.
Here's another tip: For years I've used the web site
Cruise Reviews, Cruise Deals and Cruises - Cruise Critic to gather information about cruises. There are forums where people exchange information about their experiences on particular ships, with particular cruise lines and in particular ports. On the home page on the top right there is a tab for Community. Click on it and then on forums to see reviews. I have reviews posted there under the same name I use here: Carl in Tampa.
Of course all of the cruise lines have their own web sites where you can search for cruises by defining your departure port and dates your are interested in.
When I was new to cruising I used AAA cruise advisors to find cruises. I'm sure they are still a good source if you are a AAA member. They also have brochures from different cruise lines so you can read about them at your convenience.
My favorite lines are Princess and Royal Caribbean. I like Holland America and Norwegian Cruise Lines. I dislike Carnival because they tend to have children running wild at all hours of the night,
I sincerely hope you grow to love cruising. It can be a great experience.
Carl