Plane of Hate is a good plat farming zone, especially for free to play players. The reason for this is that f2p players won’t be able to use the trading system in the Bazaar so you are going to want to farm mobs that drop a lot of plat and a lot of vendor trash. This is still a great zone for anyone who wants some extra plat though. Plane of Hate was originally a raid zone but the mobs here are real easy to kill and have low hp, so you should probably be able to start farming plat here at around level 65+.
To get to Plane of Hate you can either go through Plane of Tranquility or through the Guild Hall which is easiest. Going through the Guild Hall will cost about 50plat but you will make that back very quickly.
When you are ready to go just start blasting through the zone and kill mobs. The zone is divided into 4 tiers with more difficult mobs in each, so some mobs will take longer to kill, they still shouldn’t be a problem and you will probably find out which mobs is most efficient to farm with regards to your level.
Nothing really noteworthy drop here but the plat drops and the vendor trash is still really worth it and in a few hours here you can really make a killing.