We've found that it helps a LOT to always give 3 options. I'll admit it's hard coming up with them, but it's necessary. Customers then focus on the differences between them, instead of the raw cost. If you make some sort of training, report dev, support, etc part of the options it confuses the straight time issue (good).
For dev, be sure to include the specified development cycle: specs, draft, review, change, accept, support. Maybe put tight response requirements on the less expensive, and more flex on the higher.
We've also found that putting explicit estimates of the benefits that the customer gets from the work into the proposal also helps a lot. It's all hard, though.