So I am very new at this and just starting out with an at home cupcake business. I have figured out cost of my standard cupcakes but I need some help in pricing out a giant cupcake. I understand to factor in all overhead, cost of supplies and hourly wage, but what would be considered a basic cake that the pricing starts at and what would increase it? My guess is basic buttercream and icing designs would be the start, maybe covered with fondant is extra and fondant flowers/decorations added based on difficulty. 

Sounds good.   1M swirls are probably the most common "basic buttercream" on giant cupcakes.  Are you going to do a chocolate base or a naked cake base?  The naked cake base with 1M swirls could be considered a basic giant cupcake, with the chocolate base being considered as an upgrade unless all of your giant cupcakes are offered with a chocolate base that has been considered in the "base pricing".

(And thank you! for providing such a concise statement in your post.  There are so many new bakers who simply ask:  How much for this?")   Good luck on your endeavor!