Just like in any other F2P MMORPG, there has been a lot of controversy surrounding Neverwinter's Zen shop. I will try to shed some light on the current state of Neverwinter's F2P model by assuming a neutral stance. I hope this helps when you formulate some of your own opinions about this game.
There are three immediate currency types in Neverwinter: Gold, Astral Diamonds, and Zen. Gold is obatained through normal means and buys the general necessities to play this game such as potions, basic profession items, basic mounts, and basic companions. Astral Diamonds are obtained through special tasks such as special daily quests, skirmish events, invoking your deity, and the Leadership profession. It buys a wide variety items ranging from Identify Scrolls to rare companions to mid-level gear. It is also the only currency usable in the Auction House. Zen is obtained through paying money. It buys many luxuries that helps give paying players a better experience overall. It may also be traded for Astral Diamonds and vice versa. For simplicity's sake, I will list the price of items in terms of USD instead of Zen.
As a non-paying player of Neverwinter, you get three tokens at level 20 for a standard 50% speed horse that lasts for 5 hours. These horses can also be bought for 5 gold which is entirely manageable. To get a faster mount, you can buy Mount Training which upgrades any horse you own to 80% for 768,000 Astral Diamonds and 110% for 2,064,000 Astral Diamonds. This is progressive so you must buy them in order.
If you decide to drop some Zen for some fancier mounts, a standard 50% mount goes for 5-8 dollars, a rare 80% mount goes for 20-30 dollars, and an epic 110% mount goes for 30-40 dollars. The more expensive mounts of their respective tier has a unique model, such as the Worg and the Howler.
3. Inventory Space
You get a free bag at approximately level 10 and 30. They are 18 and 12 slots respectively. There are no craftable bags. For a free player, that means spending Astral Diamonds to buy extra inventory space. A 12 slot bag costs 6 dollars and a 24 slot bag costs 10 dollars.
A player starts out with 16 bank space. An extra 16 slots of bank space can be bought for 6 dollars.
Starting at level 16, a player is rewarded a free basic companion. These companions have two skills and have a rank cap of 15. An additional companion costs 2 gold each and may be switched anytime out of combat. All companions are disabled in PvP.
Zen buys a couple of companions which have a completely unique aesthetic. 15 dollars nets you an animal of your choice which have a rank cap of 15. 20 dollars hires a friend which has a rank cap of 20. 30-35 dollars gets you an epic quality pet that has a rank cap of 30 and three unique skills.
In Neverwinter, you gain Assets (workers) to do the work for you. Every profession starts you off with the most basic type of worker. You can have them do various amount of tasks on top of hiring more workers. Eventually you can combine 4 workers into an upgraded worker which allows you to tackle harder tasks. On top of these worker Assets, there are also tools Assets. These can be bought for 50s-1g each and have an 8% quality boost. Crafted items have a total of 4 slots for tools and 3 tiers for bonuses that is reached at 100% each.
In the Zen Shop, two different Profession packs exist: Professions Booster Pack and Professions Assets Pack. In the Booster Pack, there is 1 random (both quality and type) worker and random assortments of crafting items. In the Asset pack, there are 1 Purple or Blue Asset, 2 Purple Blue or Green Asset, 1 blue or green Asset and 1 green Asset (for a total of 5 guaranteed Assets). Any player may make any item, but paying customers will get an upwards of 20% stat increase on their crafted equipment.
You can make up to 2 characters. Two additional character slots may be purchased for 5 dollars. You may also rename your character for 4 dollars.
Respeccing your skills costs 6 dollars. Respeccing your Feats costs Astral Diamonds determined by your current level.
If nothing else, please read this part. This is potentially their biggest cash grab scheme and everyone should know how it works.
Players are given the option to add additional stats/effects to their equipment in Neverwinter. These come in the forms of Runestones (pets) and Enchantments (Armor/Weapon). For pets, the Runestones are split into Offense and Defense. For Enchantments, they are split into Offense, Utility, and Defense. A single Runestone/Enchantment provides different bonuses depending on which slot there are equipped to. These also have ranks and start from 1 and ends at 9. Four of the same kind may also fuse to move up a tier. The chance of success starts at 95% at rank 1 and 10% at rank 8. You will lose a single Runestone/Enchantment upon failure.
There are two ways to circumvent failure: Preservation Ward and Coalescent Ward. Preservation Wards cost 10 cents each and prevent the loss of materials upon failure. They are also only consumed upon failure. Coalescent Wards cost 10 dollars and guarantees success of fusion. Both these wards may also be obtained on a weekly basis through Celestial Coins (the latter being rarer). Now you may be wondering why there's a huge discrepancy between the two Wards. I was wondering for a while too until I stepped my foot into endgame and found out there was an entirely different type of Enchantments: The Armor/Weapon Enchantments.
Armor/Weapon Enchantments are for specific slots in your weapon/chest and grant special effects. They come in shards and have a chance to drop from Epic Dungeon bosses. You must combine 4 shards to create a Lesser version of the Enchantment. However, the success chance of fusion is at a staggeringly low 1%. To compensate, they have very strong effects. An example would be the Thunderhead Enchantment. However, the real kicker here is that these "Lesser" versions may be fused again to gain a stronger version. Those may also be fused again to create the strongest version. Ultimately, the Greater Thunderhead Enchantment will have a 30% on crit to damage and stun foes. To create the strongest Enchantment possible, it will cost 160 dollars and 64 shards. Unlike companions, these can be used in PvP.