A dues increase, effective October 1, 2013, was approved at the 2013 Convention Board of Governors meeting.
In addition to the monthly NSS News publication, your membership in the National Speleological Society (at less than the cost of a tank of gasoline) connects you with ten thousand people of similar interest around the world in support of cave exploration, research, and protection.
If you are not a NSS member, right now would be a financially opportune time to become one.
If you are a NSS member, the next three weeks would be a financially opportune time to become a life member at the current rates (you're locked in at the current rate while paying installments if you don't choose to pay it all at once).
The regular annual NSS dues will be increasing from $40 to $45; life membership will increase from $800 to $900. There are other membership categories at lower costs and a discount for life members over 59.
You can easily join the NSS online, as well as watch an interview with NSS President Wm Shrewsbury about the dues increase, here: http://caves.org/info/membertypes.shtml