£31.50 for a 9 inch and £60 for a two tier?? Guys, that's cheap! Ridiculously cheap in fact!! The general rule of thumb is to add up all your ingredients, gas, electricity, petrol, sundries etc and then multiply that figure by 3 to get your final price. My cakes start at £40 for a 6 inch cake, and I add £10 for every extra inch the cake goes up. So, for example, a 9 inch cake for me would be £70, and a two tier cake (made up of a 6 inch and an 8 inch cake) would be £100. Those prices would also be for the most basic of decoration (sugarpaste, a message, a few simple cut out flowers or something etc) and I would then add money on for anything more complex such as extensive decoration, models, carving etc.
I know how difficult it is with some customers, as they simply don't understand the time, skill or cost of ingredients that go into it, but a good custom-made cake is worth a good custom-made price. Even with my prices, I'm only really making minimum wage for the hours I put in, and if you're charging less than that, then you're soon going to find the numbers don't add up and it's actually costing you money to make the cakes rather than making you any profit. If you persevere with your pricing, eventually you will get the sort of clientele you want, and those that expect to get a bespoke cake for £30, will go off to Tesco's. Don't undervalue yourself or your work, because if you don't, they won't either.