If you can buy an item available on the Zen Market from the Auction House, you can always buy it cheaper from the Zen Market (during a sale or with a coupon). All it takes is patience. This game is played on the long run, if you want to eventually max out your character. If you buy everything full price, you'll progress on the moment, but it will take much longer for you to reach very end game. There are also many items you can only buy on the Zen Market, especially VIP.
You can buy Zen with real money.
Or you can exchange Astral Diamonds with Zen (player to player exchange). The maximum rate is 750 AD per Zen. This rate is reached on PC and PS4. It's better on Xbox. It can happen that no one is selling Zen. In which case, the first person to have made a proposition will be served when someone brings Zen to the market. This means that there are times you have to wait for a relatively long time to get your AD exchanged to Zen, especially on PC.
Taking Advantage on Sales and Coupons
There are big sales during the Anniversary (June), for the Black Friday (November), and during the Winter Festival (December). If you save your Zen for these, you can save 30% off of your purchases. That means you can buy almost 43% more stuff than usual ! That’s a VIP 12 for 7140 Zen instead of 10200. You are saving yourself about a month of daily AD.
If you need something at a moment there are no sales, invoke your god on many characters until you get a coupon for whatever you are willing to buy. There are 25% coupons for many of the items, 33% coupons for mounts, 20% coupons for anything. It would be a waste not to use one. A coupon doesn’t add up with a sale : if you have a 20% coupon and there is a 20% or higher sale, your coupon will have no effect. But a coupon will replace a sale if it’s better : an item will sell at -25% if you have a -25% coupon and there is a 20% sale. You get the best out of the two.
Best Things to Buy
- VIP 12 (2x 5100 Zen for 2x 6 months of VIP) : daily keys for lootboxes + tons of advantages (access to teleport, merchant, bank, 15% more RAD from dungeons, 25% reduction in the Wondrous Bazaar, no injuries…). Get VIP 12 as soon as possible (you get all of the advantages as soon as you buy 12 months of VIP, and you do not have to rank up VIP again : if your VIP expires, you'll be at rank 12 when you renew it, even if it's a single month), that’s the best investment in the game.
- Gith Booster Pack (6000 Zen, 4000 if you got the race for free on the launch of mod 17) : an epic mount, an epic companion, a 30 slot bag… all of these on each and every character you will ever create on your account ! Plus many goodies. Awesome if you have many characters.
- Character Slots (500 Zen for 2 slots) : more characters = more rewards from the festivals, and more chances to get Coalescent Wards from invocation rewards.
- Companion Upgrade Tokens (500 Zen for 75 tokens) : to get your companions to legendary at a cheaper price.
- Mount Upgrade Tokens (500 Zen for 75 tokens) : if you want to rank up one of your mount's power without having to buy a Legendary or Mythic mount.
- Wards (100 Zen for 10 wards) : you never have enough wards. Coalescent wards are only worth it when 50% off (which happens from time to time with VIP only sales)
- Bags (1750 Zen for a 42 slots bag) : you never have enough space.
- Bank Slots (500 Zen for 16 character slots, or 8 account slots) : because bags are not always enough.