Long boards are easiest to learn on as others have mentioned in the thread. If you're just wanting to learn to stand up and be able to do it easily then definitely go the long board route. Also, it'd be better to go that route since you'll be in Panama City because there are absoutely no waves at all there. And the waves that are in panama city will be like 1-2 ft high. If you're lucky you'll be there around the time a hurricane is in the vicinity.....as a matter of fact I think they're supposed to have one this friday or saturday.....a category 1, perfect for surfing.
As for shortboards, you can do so much more with them trick wise and eventually thats what you're going to want anyhow. I say get a shortboard to begin with because you're going to have to learn to surf on one anyhow. I'd also look for one that has interchangeable fins so that you can take out a fin if you just want 2 instead of 3. It might be a little more costly but it will save you money in the long run. If you don't get interchangeable fins and somehow you break 1 or 2 of them....your board is worthless. And believe me, you can break fins surfing or by simply transporting your board to the beach, as I have done.
Whatever you decide on be sure to look at the board closely. Look to see if there's any "dings" in it. A few should be expected when getting a used board but don't let those cheap fucks sell you a board thats all dinged up (dented up). Buying a decent board is a must. OTW said it'll cost at least 100$ and she's right partially, but realisticly it'll probably be around 250$ a pop for a decent used one. I just bought a new 6'6 HIC with the baddest leash you'll ever see a few months ago in preps for the upcoming hurricane season. Thats kind of short for a guy of my statute but thats how I like it.
Anyhow, that little baby cost me a little over 700$ after i got extra fins and the leash. But I got exactly what I wanted and something thats very nice....you don't need to spend anything near that amount.
Cashmotherfckingmoney
ETA: Anyone notice a difference in your surfboard preference and your snowboard preference? I use a K2 169 double wide for my snowboard.