If you acquired it fairly for $2 and didn't rape or murder anyone in the process, then I don't see anything wrong with selling it for $70...
My prediction threads:
Wii U will sell under 40m units (made on 14th September 2012)
PS Vita will sell under 20m units (made on 30th September 2012)
Wii U will sell under 7m in 2013 - I was right