I just wait till mine is almost expired and will get a call from onstar to renew. So far they offered not a 50% off, but pretty close to it over the renewal on the onstar home page price.
2011 Keystone Outback 295RE
2004 14' bikehauler with full living quarters
2015.5 Denali 4x4 CC/SB Duramax/Allison
2004.5 Silverado 4x4 CC/SB Duramax/Allison passed on to our Son!