Large Project Box/Enclosure

I am just looking for a rectangular box, preferably plastic for my project. My specific size I need is 12'' x 8'' x 3'', but I am open to sizes near that.
I've searched through the forums and google, and I cannot find one that is at least affordable. Enclosures those sizes on Hammond go for $70+.
Or does anybody have a suggestion of something pre-made that I could dissect out and just use the box?

Anything will help!
Thanks!

Take a look at the following 3 sites. These are manufacturers that sell direct to the public. They are not re-sellers and they offer great products.

http://www.boxenclosures.com/category/category.html

I have purchased from all 3 of them. I have two different sizes of the VM from Polycase and they are absoltuely awesome. I have 2 of the square minitec cases and one softcase from OKW and they are awesome. I have one Series 50 from Box Enclosure and while I really like the silicon boot, the case itself does not seem to be as well made.

I would strongly urge you to look at OKW. They have a great range of different styles and I was really impressed with both the quality of their products and their customer service.

This has the dimensions you posted --
http://www.ebay.com/itm/Aluminum-Project-box-Enclosure-8-X-12-X-3-GK8-12-3-/270894456572?pt=BI_Electrical_Equipment_Tools&hash=item3f12915efc

The shipping is steep. Exorbitant s/h at ebay has turned into a de facto minimum bid and they ought to crack down on it.

..or you could get a cigar box