AIts so hard to say because pricing is something you have to work out for yourself. Its all based on your costs.
if you do a search on here you'll find a ton of pricing threads with some really really good information that will help you determine if you sold yourself short
i think your cake is lovely and your workmanship is very good--
all that to say as to pricing-- this not a cake design that i would upcharge for anything--it would be just straight up normal pricing--per serving pricing 32 servings times $X.XX--unless you use pounds or euros ;)
well i would want to charge for ombre layers though--don't know if i would but that'd be all--probably would not though--maybe if it was super elaborate--
if you look around on other people's websites you will get a wide range of prices--probably anywhere from $25 (faint) to $180 +
so my recommendation is that you aim high ;)
best to you
ACheck out the Pricing Formula link in my signature below.
I would definitely price the cake on a per serving basis! Any extra work involved can also add to the price, like the customized plaque.