A couple more thoughts:
Another good idea if you want to see prices and body styles is to look on e-bay. You can pull up all of the 65-69 Mustangs and put the ones that interest you on a watch list. That way you can see some different styles, mods, etc. Check out what they end up going for at the end of the auction. But, beware--don't get all caught up as soon as you see one and go hog-wild bidding on one. And, I can't say enough--let the buyer beware if you do find one on e-bay! Since you are not familiar w/ classics, think of e-bay more as an information resource for you than a strong option for where you will actually buy a car (unless it's possible for you to see it in person).
Go look at a couple of local classics (Mustang or otherwise) that are for sale and drive them. My first 2 cars were a 71 and 69 Chevelle years ago. I have kicked myself for years for selling them, and kept getting a wild hair to buy another classic. About a year ago when I started considering actually BUYING another classic, I told my wife that I was going to take 3-6 months and decide if I was serious or not. Who knows, you might decide that the ride, options, etc. of a 40-year-old car just aren't for you.
Also, (Sorry. I get long-winded sometimes.) do as someone suggested and go to a car show. Pics give you an idea of what you're looking for, but seeing the cars in person puts them to scale for you. You can get a better feel for what features you like/dislike or want/don't want. Take your camera and snap some of your own photos.
Again, best of luck in your search. I hope in the not too distant future you look out in your driveway and feel like you got exactly what you wanted!
Bryan