>>348320>Looking for a dirt bike to explore on>also be comfortable on the road>fit a student budgetEverything's a compromise, especially in the dualsport market. Good luck finding something that meets all three req's.
My KTM's a pretty badass machine, for what I use it for. Does great offroad. Eats up milder singletrack. Can do highway. Doesn't have a lot of storage/luggage options. 50mpg-ish around town. Needs a piston about every year (~6k miles).
On the smaller/cheaper side, you've got the older tiny bikes.... CT90, 110, ruckus... glorified scooters IMO. These won't be doing highway speeds, unless they're assisted by gravity. These certainly meet your "student budget" requirement.
As you move up, you'll get into the enduros and lighter dualsport bikes. DRZ, some KTM's, WR's. A little better off-road, a little better on the street, but more expensive.
Moving up from that, the KLR650's a good option. Relatively inexpensive for what you get, but not nearly as capable off-road as the smaller bikes. Better (longer) maintenance intervals too.
Going bigger still, you get into the adventure bikes... DL650/1000 ("V-Strom"), KTM Adventure, BMW GS are the big ones. Great for knocking out miles, they'll do some lighter dirt roads (in the hands of capable rider, can keep up on two-track or ATV trails... know a few guys who singletrack 'em). Super-expensive though ($8k+, for something in decent shape).
Keep in mind any of these bikes can be taken just about anywhere - really more on the rider than the machine. I've sno-x'd my long-track mountain sled before, and I've done MX on my 525. A purpose-built machine would certainly work better, but I got it done.
Mine's starting to look more like a dirt bike again; pic related, in the garage right now. Run some parts across the mill tomorrow and finish out a few more parts orders... hopefully by the end of the month i'll be riding again.