This is also on the Gandi IDE website.

NG or Naquagems is a 'currency' that you can earn on the discord, Gandi Community Events, or from other scratchers. To put it soimply there are 3 types of exchanges; Discord Nitro, Robux, and Amazon Giftcards. Every 1,000 NG = $1 but you can only exchange it for any of the previously mentioned exchanges if the value is over $5 (aka, you can only get something once you have over 5,000 NG to exchange.)