I don't like to give $0 to reg fee appraisals without a reason so here are my 2 reasons:
1.) You can currently handreg TEN NNx.org domains so that means out of the 100 possible combinations, 10 are available, 10%
2.)There are no past sales to compare .org by (If that tells you anything) but here are some .com's and .nets which are more valuable than a .org in this instance..
44x.com 2,499 USD 2017-03-02 Sedo
87x.com 4,300 USD 2017-02-28 NameJet
70x.com 4,500 USD 2015-06-15 Sedo
50x.com 4,500 USD 2015-05-14 Sedo
02x.com 2,000 USD 2014-04-30 GoDaddy
26x.com 764 USD 2013-06-09 NameJet
43x.com 225 USD 2012-04-11 NameJet
51x.com 2,600 USD 2010-07-14 NameJet
37x.com 755 USD 2008-03-16 GoDaddy
92x.net 180 USD 2016-02-12 GoDaddy
07x.net 4,794 USD 2009-07-29 Sedo
At the end of the day though, your domain is only worth as much as someone who really wants it is willing to pay for it, which could be $1 OR $1M