Paradise is indeed Free to Play.
Main difference which you noticed is due to this server is diamonds, not gold based.
Price of diamonds depends of quests gold rate - it's higher here than on other publishers, and every new zone bring more and more gold from Daily Quests.
A lot of things (included diamonds) you can obtain without investing money.
- you can obtain diamonds for ancient mementos
- you can obtain diamonds for gold from Auction House
- you can obtain diamonds for gold from NPC
- you can obtain diamonds for selling items in Auction House
- you can obtain IS items spinning Wheel of Fortune
- you can obtain IS items and gifts from our event NPC's located in Varanas
- you can obtain IS items from several of minigames
- you can obtain IS items from our regular festivals
- you can obtain IS items from community events
Additionally you can get VIP member which allow you to receive daily gifts every day or meet Travelling Merchant who will sell you high valuable items for attractive price.