Feeling the need to chime in here. I'm a hobby baker and just do cakes for friends and family. I have been considering starting a cake business so I have spent some time figuring out costs.
The thing is, cake materials and supplies are very expensive, and the cost of food is rising. Granted, I do not buy supplies in bulk like someone who bakes for a living would do, but I figure it costs me about $40+ to bake a two tier cake about that size. It's not just flour and eggs, there's food coloring, cake bases and cardboard rounds, gumpaste, and tons of other supplies.
When you factor in the overhead costs for a baker to run a kitchen, plus their time, $150 for a cake is not unreasonable at all.
I can totally understand why someone who was living on a budget would not want to pay that much for a cake, I just wanted to share the other perspective.