Where I work part of our uniform is basic black work pants. They issue about three pairs of pants to us but they are so hideous and the fit is horrible. They come up to probably the bottom of my rib cage and I'm a walking billboard for Dork of the Year. :o) We are allowed to wear our own black pants but they must be of the Dickies brand. So off I went to Walmart to pick me up a pair so I wasn't nominated for Dork of the Year.
They had one left in my size at the Walmart I went to and they were very reasonably priced for $19.99. I'm sure you could get bigger sizes online but in Walmart I believe they had sizes 3 to 15. The pants I got were basic black, regular length, and have one pocket in the back on the right butt cheek. These pants are quite comfortable and defintely very durable. I work 12 hour days where I sit at a computer all day so often times I am eating my lunch and dinner at my desk so I can't tell you how many times I've spilled on my pants. They wash up really well and nothing has ever really stained them. I own two pair and I wear them usually twice, sometimes three times if I'm really desperate and then throw them in the wash. I am also able to throw them in the dryer each time without having to worry about them shrinking and becoming a little tight as jeans do when you dry them.
Overall I am very happy with my Dickies and the brand as a whole. If you need basic work pants I highly suggest you check them out. I do believe they have quite a variety of different types of pants, including khaki ones. You are definitely getting some great lasting pants for a great price.