Join Date: Nov 2007
Location: The Land of Jersey
You should be able to build according to your specs for half that material cost, and still use wood products. The white board you referred to is probably melamine, not MDF. MDF comes in 4x8 sheets, is brown and looks like pressed/smooth cardboard. It is fine for what you want to build so long as you are only using it for the case (box) not the frames, drawers, or doors.
You can buy paint grade plywood from the home centers or a local lumberyard. For a good paint grade harwood for your frames you can use poplar. Harder than pine and paints well. It sounds like you may have bought "clear pine" maybe, which is considerably more than #2 pine.
Price point for a DIY guy is going to vary considering those of us who do this for a living either buy rough sawn lumber in quantity and mill it ourselves, or get a nice contractor discount from a local supplier. I do both, but sometimes find myself on a Sunday running over to one of the home centers to grab a couple pieces of poplar to finish a project. The cashier usually has to pull the cash out of my hand because it kills me to pay that much for something I normally get for so little.
I know at my local HD, they sell a 4x8 sheet of Birch for around $48.00.
They also sell some garbage called sandply for around $29.00 a sheet. Sometimes the extra money spent is worth not having the aggrevation that inferior products can produce.
For the project you described, I'd probably get between $900-$1,200 but it would started and finished in two days. So my goal of material costs may be different from yours. Good luck! Show us some pictures.