Path of Exile, often referred to as PoE, is an online action role-playing game. You are playing as an exile, sent to Wraeclast, a dark place where exiles are taken. There is no gold in Path of Exile. Instead, the Orbs are used as currency, with Chaos Orbs and buy Exalted Orbs being the primary baseline currencies.
You may be tempted to try to improve your character as much as you can each level, but you have to understand that the currency you find when you are level 8 can be even more useful to you at level 80. I'm not saying keep everything stashed away and never touch any of it, but only use what you need for very large upgrades to keep your build running smoothly.
Because there is no Auction House, Trading between players is the only way for players to exchange items. The actual act of trading is easy; you simply form a party with another player, meet in the same location (usually the hub town of a particular act), and right-click on their name in the party window and initiate the Trade. It is a common and secure “accept” interface, but one interesting part is the game requires you to mouse over the items you are receiving in order to ensure they are what was agreed. This is a nice check to support honest trading and to make sure each player actually confirms each of the items before approving the transaction. There are also numerous public Trade Channels which are extremely active.
Unfortunately, trading is not easy in PoE. Because it is an item-based economy, there is no real consensus on the value of items. While there are websites that attempt to represent the value of currency (such as poeex.info and exilestats.com) and even items (poespreadsheet), players still bicker over value and price, usually using the site that shows a lower value to purchase and a higher value to sell. While many players will agree upon general “ranges” of value (such as Chaos to GCP ratios), each item transaction usually ends up being an effort of bartering and haggling.
Merchants play a very important part in the game as they serve as the “conversion” base for items to orbs (or Scrolls of Wisdom for identification). When you sell items to Merchants, they reward you based on the type of item and the combination of items you are selling. This is where Vendor Recipes come into play, allowing the player to focus on gathering very specific items in order to acquire the Orbs they are looking for.
When it comes to acquiring items based on vendor recipes tied to properties (such as attribute or resistance mods), you must first identify the item to get credit for the properties (whites of course do not need to be identified). Players who are actively looking for any and all orbs they can get their hands on will often pick up all blue items and identify them in the hopes they can acquire the orbs they are looking for. The recipes a player can pursue are very extensive.
You can also create Rings, Amulets and random Magic/Rare items, and decrease Skill Gem levels and increase the level of a Map by selling a combination of items to the Vendor.
While this may be fun and interesting to some, it’s actually quite burdensome to most and players must spend a large amount of their time haggling with others for acquiring or selling items. Right now, players can create store fronts in the PoE forums and then use tools like POE Goods to browse those stores, but it is still very clunky and burdonesome to contact the owners of the stores as you can’t tell if they’re online until you attempt to send them a tell.