Can someone please tell me the number of servings for the 9x13 and the 12x15 Wilton sheet cake pans? The 2 inch deep pans and just 1 layer of cake. 1 and a half x 2 inch servings. Also, when YOU make these for parties, do you charge for 2x2 inch servings or do you charge the same amount per serving reguardless of whether its for wedding or birthday? Thank you!

It's easy to figure it out. Take a piece of paper (or mark on the bottom of the pan) what size you want the pieces to be.
I usually have a set price for non tiered cakes - usually single layer (usually split and filled). For a 9x13 I would charge around $35. For a 12x15 about $45.
When I make a tiered cake the price is $XX times the # of servings. A wedding/tiered serving is 1x2x4. My reasoning is that one spends much more time and talent on making a tiered cake be it for a b'day, shower, wedding or whatever. It takes more time, more ingredients (2 layers), more filling, more work and sometimes more icing. You make flowers (usually many, many more; more elaborate); maybe lace pieces; attach ribbons; you need to take more time to smooth well, plan out everything involved; gather boards, etc, etc. Just overall it's much more work.
A sheet cake or other shape be it for b'day, shower, or whatever usually is not much more than iced, slap on a few flowers and borders and your done.

Industry standard is 1x2x4 inches or 2x2 (single layer). I don't sell cakes but I think to keep it simple I would charge by the serving whether it be 2x2 or 1x2x4.

If I do the math (and I could be wrong ) this is what I get for 1.5X2 single layer servings:

39 servings for the 9x13.
60 servings for the 12x15