NHaler or vapors4life have good KR808D-1 style starter kits for about $50 (use saveinnj and smilin coupon codes), while vaporetc has a good basic KR808D-1 starter kit for $37. These kits use cartomizers, but cartos can be refilled, and blank cartos are available (the vaporsetc kit actually includes 5 empty cartos and an initial bottle of juice).
Pick up a passthrough, and a car power adapter (flips the cig lighter to a USB 2A output, to power the passthrough), some extra liquid and blank cartos, and you're still under $100.
Otherwise, Liberty Flights has super deals on the Riva 510, should see some more in within a couple weeks -- they go fast, but $30 is a sweet price point, leaves plenty of $ for a passthrough, car cig-lighter-to-USB power adapter (to use in the car), etc.
The basic 510 has a reputation for kind of poor battery life (use time between recharges). Riva and eGo have much larger (higher capacity) batteries. In the 808 family, standard batteries are good for a couple hours, the XL or Mega battery is about an inch longer and noticeably longer running time, and I now also use a G400, a very high capacity 808 battery.
(The 808 and 510/Riva/eGo are two of the bigger selling standard lines, with good parts availability. I use the KR808D-1 family, which have true 3.7V output (more vapor for a given resistance atomizer/cartomizer) and good cartomizers , though many love the 510/Riva/eGo.)
There are a couple of decent disposable 510 kits, $13 at litecigusa, if you just want to try something out.
Good luck!
