Something you'll discover soon as a new Wyvern player is that gold is the main bottleneck in progressing with the game. Experience points and items are generally plentiful, but for most races, training skills are what makes a player stronger. Only Rakshasas and Nagas get stronger as they level.
How to make money
There are various ways to make money -
1. gem/gold spawns - many areas in Wyvern spawn gems and gold which can be picked up, ranging from 1gp-500gp in value.
2. monster loot - some monsters drop items that you can loot and subsequently sell to stores/players
3. loot spawns - some areas in Wyvern spawn loot, that can range from Dragonscale mails to bags of vast holding. One that comes in mind is Tehur, an obscure cave located between Stensele and Bandar Gaah on the world map.
The Merchant skill increases the amount of money you receive from selling items to the store. This is your bread and butter.
At level 1, the max amount of money you get from the store, is 500gp. Each additional level of merchant increases the sell cap by 250gp, maxing out at 3000gp per item. This is your bread and butter. This skill is expensive to train, but the most sound financial investment in Wyvern one can make. The cost of training is (merchant level)*5,000gp, ranging from 5,000gp for level 1 merchant to 50,000gp for lvl 10 merchant. Dwarves can train up to 20 merchant (total cost ~2.5 million gp :P)
With the current loot system, there are only a small subset of monsters that drop good loot that are shop-worthy.
Monsters: Kobolds/golbins/troglodytes/orcs -they drop tiny shields, or javelins
Location: Davos, New Verden
Monsters: Elves/Dark Elves - these monsters drop loot like elven boots, elven spears, leather armor, etc., that sell for 25-500gp. Rarely, they drop elven wizard cloaks, and wands.
Locations: Minath Houses (most popular), Khaytsi Forest East, Macabre Elven Refuge(lvl 15+ to access), Minath Ruins, Tehur (15+)
Monsters: Ice Vortex/Bone Devils/False Angeles/Horned Devils/Soul Takers/ Blue Reavers - these monsters are all melee, and don't cast offensive spells. They're really weak, but they drop every type of wand, spellbook, and many potions. They can sell up for max value (500gp at 0 merchant, and 3000gp at 10 merchant!) I find these to be the most efficient monsters in terms of difficult/gold yield ratio
Locations: Khaytsi City, Glacier Point Ruins, Issrano (first map is beginner friendly), Bura Shaan, Tehur
Monsters: Medusas/Naga Zombies/Mermaids/Rakshasa Ghosts
Locations: Glacier Point Ruins has a few medusas. Ancient Vesimas is where you will find Naga Zombies and Mermaids. Rakshasa Ghosts are found in macabre, and have a 20% chance of dropping spellbooks and scrolls.
Monsters: Riagors/Witches/Medusas/Kalidemons/Xipe Totecs/Frozen Medusas
Locations: Random Dungeons level 20+
Most higher level players get most of their xp and loot from random dungeons, which not only spawn loot randomly (loot you find in general stores, which can include armor, weapons, bags, quivers, etc.) but also have higher level demon-type monsters that drop magic items like spellbooks and stuff.