I have a bride that wants a 5 tiered wedding cake with LOTS of fresh roses (organic) cascading down the cake. She's only serving 150-200 guests. I told her I can make the cake into 4 tiers to serve the amount needed, but she wants 5 tiers so she is now asking about a dummy cake. My question is, how do you charge for a dummy? Do you just charge for the cost of it? I've never used a dummy before...
Also, all those roses--how do you attach to buttercream?
I would charge the same, because you still have to take the time, effort and supplies to decorate that dummy tier as you would the regular one.
If you're not comfortable with that, maybe figure out how much it would have cost out of your ingredients, supplies and hourly cost to bake that tier and compare that to the cost of the dummy alone.
I charge slightly less, since I don't have the baking time for dummies. I'd still charge at least 80% of the regular price, though, more if the design is complicated.