I gladly take custom orders on throw pillows of small sizes. Sometimes those little cute decorative pillows are hard to find. I make custom throw pillows up to 13". As for the larger pillows, usually I don't make those myself, as they can be easily purchased in the stores like WalMart, plus the shipping will be too high: they will require a box for shipping and due to their weight can only be shipped via Priority Mail. For larger pillows, I only crochet a lacy pillowcase which you can use on your own throw pillow.
I make little pillows in cotton or acrylic yarn (your choice). The insert is Poly-fil. The pillow cover is not removable, but the pillowcase you can take off and wash.
My acrylic pillows ARE machine washable though, you can machine wash and dry them. Just take off the pillowcase first and make sure you use delicate cycle. As for cotton pillows, I don't recommend washing them in the machine, even in cold water, because they can shrink and pillowcase will not fit anymore. Plus, some colors may run. Better dry clean them, to be on the safe side.