I just got a passport at christmas time, i visited belize,mexico, and roatan and some other places in that area. Other than a couple very small trips to mexico thats it for me.
The us is huge and there is tons to see here, ive been to almost every state here and i still find it entertaining and interesting to just see things around here. as far as being cheaper to go to europe than across the country I seriously doubt that. for every "cheap" plane ticket to europe you can find an even cheaper one across the us, not only that but flying isnt the only option. Most people need to see more of our own country before they start seeing crazy foreign things.
even still i have wanted to go visit over in europe for quite a while. I even convinced my parents to give me 1k to get me started. The only problem i see is time. I want to spend at least 1 month there, maybe 2. I think I can easily afford the cost, but when I come back I wouldnt have a job
That and my roomate and i are much too lazy to start planning.