Where to buy a large touchscreen+display kit for < $300

I building a touchscreen keyboard for PC. For that I need the cheapest available multitouch touchscreen + graphical display combo. Screen Size around 10 inches Please suggest me a model, which I can order online. I have been looking everywhere but the ones I find are expensive and come with features I don't need. Thanks.

multitouch screens are still expensive (the profit pays for the development)