Forum threads
like this one indicate a stylus made for a tablet PC is the most likely to work. It's encouraging to see in your eBay list that for those various models of Gateway tablet, there's apparently just one and the same stylus needed.
A stylus meant for Intuos or Cintiq is not likely to work. Those are Wacom's advanced models of tablets for which the technology has - AFAIK - never been licensed to OEMs. I can also tell you from personal experience that the stylus for a Wacom Sapphire (a budget series tablet) doesn't work.