TradeMe are advertising free selling today, not uncommon, happens every couple of months.

However this time they have removed all payment options except Ping, which deducts 2.19% from what you get paid.

The success fee is free today!
All payments for items listed today will be made through Ping. It's the safest, fastest, most secure way to get paid. Cash and bank transfers won't be available.

Ping can be quite useful and generally works OK, but should never be the only payment option.

So, not really free listing at all. But the worst thing is you can't override it and accept the usual sales fee just to be able to get other payment options. Bad luck if you want to start a normal auction.