The most common pygmy available in the US is O. mercatoris - usually misidentified as O. joubini. They are common in Florida waters and LR farmers such as Tampa Bay frequently collect them. Price is usually in the $20-30 range plus shipping, although I have seen them for less. O. mercatoris breed in the spring and often you can get a female with eggs. Normally that would be bad since she will be dead in two to three weeks. However, we have had success rearing the juveniles and at least that way you will have one for several months. The down side is that they are very nocturnal. We never see ours until after dark and as soon as the lights go on, they are back in their shell.
O. bocki is common thorughout the Central and Western Pacific, but they are difficult to keep. I prefer O. wolfi, but they are not quite so comon.
Roy