I haven't been to too many countries (Canada, Mexico, UK, France, Italy, Switzerland, the Vatican), but I've been to 38 of the 50 states. I just finished school in December, so I understand not having any money, but my theory is that you either make the time and money for it, or you don't. You make all of your own opportunities when it comes to that stuff. I drive a paid-off Civic that gets good mileage, and when I want to go somewhere I get in the car and ing go. I Priceline hotels for cheap, stay in bed and breakfasts that are sympathetic to students (unforunately I had to cancel my reservations at one in Niagara Falls on the Canadian side that I found for $35/night). When I lived in Michigan I drove all over that part of the country, and when I interned in Yellowstone this past summer I drove all over Montana, Wyoming, and went to Canada - not to mention the awesome road trip up there from Texas. Manny and I did a trip out to Guadalupe Mountains, Carlsbad Caverns, and the Davis Mountains for less than $250 including gas, you just need to know how to budget, be flexible, and not mind going without some things.
Another thing - keep up with restaurant weeks in places that you are thinking about going. I just moved out to Santa Fe, whose restaurant week is currently going on - I am trying a ton of restaurants that I would ordinarily never be able to afford to go to on a librarian's budget.
As for international travel, keep an eye open for airfare specials - if you know people who live where you want to go, keep in touch with them so you have cheap travel guides and possible accommodation. There are crazy travel specials all the time if you've got a flexible schedule - subscribe to email lists like IgoUgo and all of the MSNBC travel tip RSS feeds. Google Reader is your friend.
Also, Italy was amazing, but I didn't make it to Milan - I went to Rome, Florence, and Venice - all three definitely worth seeing, and all very different.