I'm a general contractor that specializes in finish work and cabinetry, and I keep telling people doing DIY stands/cabinets about this place that I think gives the best deals around on doors.
Mill yards like this usually are where even many custom cabinet shops get their doors just because the price is so cheap, it's really about the same as what material costs me for STAIN GRADE material.
I just happen to like this place, it's a cool older lady that runs it, and they give by far the best price I've found, and excellent quality.
If you're building your own stand, you might want to check this place, Doors Unlimited in San Marcos.
Raised panel doors like this are very time consuming to build on your own.
I just did this bookshelf/window seat, and I got all 9 doors for $210 total, done in stain grade birch.
If you want to do a nice DIY and save some time and money I strongly recommend this route.