To be honest Ted it doesn't sound like you did much wrong (with the possible exception of the -a flag but that wouldn't break it in the way you describe)
I would suggest that you have faulty hardware, take it back and get a refund for some beer or buy one with a recognisable name (you can pick up 1GB Kingston sticks for less than the price you paid).
You seem to get a little be confused at the end /dev/sda1 is not a mount point, in this case it is a virtual device node assigned to the first partition on the stick by the USB Mass Storage controller, if things are not getting that far then either a. Your USB is broken b. The device is broken or c. The device doesn't use the standard USB Mass Storage Controller. /dev/sda is the lowest level you can talk to the device as a block device.
Seeing as it almost worked once I would suggest b, particularly now if you can't even point fdisk at /dev/sda to wipe/create a new partition.