⇄ You can buy and sell Namecoins here:

Decentralized exchanges
(uses atomic trades; memory-safe)
(uses Tor by default; memory-safe)

Gold level exchanges
…

Silver level exchanges
…

Bronze level exchanges

Basic level exchanges
Coinvex
CoinEx
FreiExchange
Komodo
NLexch
Coingi
AltCoinTrader

Gold, silver and bronze level exchanges donate to the Namecoin project. The higher the donation the higher the level. Note that the exchanges are not verified in any way. The current fees are 1000/300/100NMC per year. To get on the list contact exchanges a|t namecoin.org