April 30: Not exactly free, but...
There is a NC Mall Supersale starting today, ending at May 1, 2011. The majority of items are 50% off, so if you have some spare NC, why not visit the NC Mall
today and see what you can buy.
Earning NC at Petpet Park
Now we usually do not post updates on Petpet Park but currently there is an event going on at Petpet Park that allows you to earn NickCash. Which is the same as Neocash and is exchangable on all Nickelodeon Virtual Worlds (Neopets, Petpet Park, Monkey Quest).
In the event you have to help Neeter build his Game Machine so he will send you on all sorts of quests to test games or to find more information from other characters in Petpet Park. If you want to do this quest, you must go to Petpet Park, click on the Map and then visit the place valled Pawvillion. There you will find Neeter (the green fellow in the picture below), if you click on him you can start doing his quests by clicking on the yellow conversation starters. Once you finish a quest you can start doing a few more by returning to Neeter and clicking on him again. In order to finish helping him with the Game Machine you must complete quite a fair amount of them. Not all of them will be available to you right away. Petpet Park releases them at a batch each time, so you must continue to return and check if there are new quests. Yesterday the second batch of quests was releases. Unfortunately, we don't know how many quests there will be or now much NC you can actually earn with this.