I plan to sell some, but i am very unsure of what size box to get
I buy 19x14 boxes and buy the coordinating cupcake insert for the box for both 12 and 24 cupcakes...when you are purchasing the boxes it should also show you the different inserts for cupcakes..or most box companies do anyways!
Quarter sheet for 12 and half sheet for 24, with these inserts:
4 cupcake inserts are made to go into a 7x7 box
6 cupcake inserts are made for 10x10
12 = 10 x 14
I'm not sure about 24...I've always just used 2 boxes of 12.