Hello,

Here are my specific questions, please see below for context:

A) Is it feasible to show up at a major airport with a credit card, a
passport and a carry-on and expect to get a cheap international seat?
How would I do it? [most important]

B) Are there websites that feature deeply discounted international fares
or last-minute deals that allow for general searching of geographical
destinations? [less important]

C) What is the least can I reasonably expect to pay for a fare of these
types? [less important]

The Story:
I have a vacation coming up, and I want to travel internationally (and
inexpensively!).  I want dirt-cheap airfare to anywhere in Central
America, South America or Spain. I am only interested in ~10 day,
round-trip travel from LAX or the Northeastern US (NYC, Boston,
Philly).

I can't find any online sites that let me search for either a)super-last
minute, restricted fares or b)search for destinations in a larger
geographical area than ~50 miles.  If it will save me money, I am
perfectly willing to show up at an international airport with a bag
and fly to wherever there is a cheap last-minute airfare.  However, I
can't find any indication that this would work or be particularly
cheap.

Thanks!

http://www.delta.com/planning_reservations/deals_offers/fare_sales/atlanta_keywest_montreal/index.jsp

Puerto rico cold be cheap and very interesting
Good luck