A T-bone combines a strip (think NY Strip) and a smaller portion of the Tenderloin (the Porterhouse has the larger tenderloin filet section). 
 
Base price shown is rated for 1 pound of meat. Price adjusts by weigh of specific cut.
 
The weight range for sizes are:
 
Medium: .75-1lb
Large: 1-1.25lbs
XLarge: 1.25-1.5lbs