I have 2 lug studs broken on my rear tire because some ahole snapped them when changing my tire. Are these hard to replace? I haven't taken the wheel off yet to investigate...

 

$5 a stud from any garage. If you have air compressor and tools you can change it yourself plus the cost of the studs.

 

Studs:
~$2 at Pepboys/Kragen
~$4 at dealers

Piece of cake if you have compressed air hammer gun, otherwise, have a tire shop do it for you. Don't try to remove the broken stud with ordinary hammer as you may bend the wheel mounting plate.