This page of The Witcher 3 Wild Hunt guide has information on how to collect gold with ease. We also write about, e.g. the available currencies, limitations when it comes to trading, or items that you should sell first.
In the original books, witchers never had much money. Wild Hunt is loyal to that rule. At the beginning of the game, Geralt has trouble with accumulating decent amount of money. Expenses are large and there are only few sources of income. At least, ones linked to monster slayer profession. If you want to repair your equipment on a regular basis, buy better armor and swords, you must utilize all ways of increasing your income. In this chapter of the guide you will find advice that might help you with that.
- There are three currencies in the game: Temerian orens, Nilfgaardian florens and Novigrad crowns. The latter is a commonly used currency in the game world. It makes other two useless in standard transactions with merchants. Luckily, there is an exchange office in the game. You can trade foreign currency in Vivaldi bank on the marketplace in the free city of Novigrad.
- Vivaldi Bank can also grant Geralt a one-time loan if he asks for it during a conversation. The amount of money given won't be large (100 Novigrad crowns), but at the beginning of the game even such amount is useful. Despite warnings from the dwarf that it must be repaid, you shouldn't worry about it. Yennefer is the guarantor of the loan. It means that you shouldn't expect any thugs trying to force you to repay it.
- Various witcher contracts are the most profitable tasks. If it is possible, you should bargain before accepting a contract. Placing the slider more or less in the middle will allow you to sense how much additional money you can get. After eliminating a creature, you will receive a unique trophy. It is a proof that you have completed the task and you won't receive money without it. Trophy can be sold later if its stats don't apply to you. All unique items are valuable.
- At the beginning, it is a good idea to collect all items from defeated enemies and then sell them to merchants. It applies especially to weapons used by thugs. You can be a herbalist as well. Common plants aren't expensive and collecting them takes time, but they are available in great amounts.
- You should check the value of items at different merchants in the neighborhood. An armorer will pay you slightly more for useless breastplate than a common merchant who offers typical items.
- Collect ingredients required for decocting basic potions as quickly as possible - especially for Swallow which regenerates health points. You don't need to recreate once boiled potion, at least until you gain a receipt for its stronger version. If Geralt is in possession of alcohol called Alcohest, potions are replenished automatically during each meditation. It is commonly available, so you shouldn't have trouble with accumulating it. After you get the Swallow, you can sell all food and weaker alcohol (every type of wine and beer).
- Merchants don't have limitless amounts of money. Their wallet size is regenerated after some time. You can stimulate circulation of money at the armorers, by ordering them to make items or by reclaiming ingredients. Money offered to them can be regained by selling them other items.
- Try to equip Roach in better saddlebags as quickly as possible. They allow you to carry more items and reduce the amount of trips to merchants.
- In the beginning of the game you should develop a habit of searching through all containers (chests, packs, barrels). Interactive containers are marked with yellow color in the Witcher sense mode. Avoid stealing if there are guards nearby, it might lead to conflict. If you are defeated in such a battle, repercussions are similar to Gothic series - your character can get up, but he will lose some money.
- Alchemical ingredients differ in availability - the harder it is to get them, the more expensive they are. Keep that in mind when trading. Sometimes it is better to keep items required for creating a better armor than sell them for a nice price. You should browse available schematics often and plan future crafting.
- Sell books and documents you have already read, even ones obtained in main quests. After reading they become useless and they only waste precious space in the equipment.