This page will contain everything you´ll need to know about Trading
General Info Edit
Sorry, i forgot a lava bucket
Each Profession has a seperate set of trades. Before 1.8 the order trades would be unlocked was random and chances to get a certain trade varied (exact numbers would be good here). In order to unlock a new trade you had to trade the trade in the last slot. Then the villager can do three different things. First he unlocks a new trade and resets all other trades, second he doesn't unlock a new trade but lowers the price for an existing trade and unlocks all trades again or third he only unlocks his trades. The book trades the librarian offers are also affected by this behavior but when checking for a cheaper trade he only checks if the emerald count is lower not if the actual to 17 emeralds and below. At this point the emerald count does come into effect as to how high the enchantment can be. (explained more in detail below) When the Villager has all possible trades unlocked he can always be reset using the last trade.
Perfect Villagers Edit
Perfect Blacksmith: A perfect blacksmith has a desired trade in the last slot. A desired trade would either be the Iron, Coal or Gold trade, depended on the given infrastructure, because you earn emeralds doing it. Blacksmithes are especially useful because they offer all Diamond Tools and Armor Pieces.
Perfect Librarian: the perfect Librarian has the Paper-Trade last since it is the easiest the farm a big amount of.
Perfect Priest: the Priest mostly interesting because of its ability the enchant tools and armor for a low emerald count. Since Priests only enchant between levels 5-19 the most desireable trade would be an Efficiency III, Unbreaking III (, Silk Touch I) Diamond Pickaxe, which is perfect for instant mining in the nether.
Book Trading Edit
Because of the risk of resetting the Book-Trade booktrading was not very popular in versions before 1.8. However the villager will only reset his trade if he is in the same dimension as the player. Using Nether Book Halls players could trade a book trade forever by just moving the villager with a minecart and sending him to the overworld. There he would be automatically get moved back to the nether and return in spot in the Trading Hall.
Trading 1.8+ Edit
In 1.8 Careers were added to Villagers causing them to get different sets of trades for same appearences. Also a lot of Trades were added or changed.
- Butcher (Butcher/Leatherworker)
- Farmer (Farmer/Fisherman/Fletcher/Shepard)
- Blacksmith (Armorer/Weapon Smith/Tool Smith)
- Priest (Cleric)
In 1.8 Villagers always unlock trades in the same order and they dont change the cost of their trades anymore. Also the number of trades unlocked on a new Villager is now 2 or higher depending on Profession and Career. Additionally the last trade is not guaranteed to unlock all trades anymore. Now Trades can be unlocked by doing other trades, therefore Villagers with a lot of cheap Buy-Trades and easy Sell-Trades are the best way to obtain emeralds. The best choice here is the Farmer since in 1.8 the VillgerAI changed and they harvest crops automatically now.
Additional unlocking information for mass emerald stockpiling Edit
First off the mechanics for unlocking have 2 factors: chance of all trades unlocking and number of times you can trade each trade. The first time you trade a trade of a 1.8 villager (1.7 villagers may take more than 1 try, but once you get to the 1.8 trades they act as normal), they will have a 100% chance of all trades unlocking and the next tier becoming available (if not unlocked fully). Afterwards each trade will have a 20% chance of reunlocking all trades whether you only trade once or max out the trade in 1 go (I'm 99.9% sure the "1 vs maxed" is correct after trading ~50,000 emeralds over time in 1.8.) That in itself is hard enough to keep villagers unlocked, but here is where the second factor comes into play. Trades have 2-12 tries before you cannot trade that trade anymore and have to exit the gui. This number of tries is random and does not reset after you exit the gui without maxing out the trade. This means that you can have 1-12 tries in actuality. This is very bad with villagers with only a few trades ex. Tool Smiths only have 6 trades (if pure 1.8). Be sure while emerald collecting to refresh the "try count" on trades that you only use to reunlock the trades. (for example on the tool smith the shovel.) If you do not do this it is very possible to lock out the villager permanently: As if you are incredibly unlucky you can get all trades down to 1 or 2 tries left and with only the 20% chance of all trades being unlocked it is possible to lock out villagers forever.
Perfect Villagers Edit
In 1.8+ a perfect Villager has the all the best possible trades.
Book Trading Edit
In 1.8+ Librarians have 3 Book Trades each, with the enchantment level reaching from 1-30. Therefore every max level enchantment can be obtained by Librarians, allowing you to never need to enchant again. (instead making everything through anvils) This and the fact that these trades will never reset made Book Trading very popular. The low prices are also a big advantage over normal enchanting. The table below shows the minimum price per enchantment level.
The formula to calculate the lowest price: Enchantment level*3+2
1.7 villagers in 1.8 Edit
Villagers from 1.7 will not always carry over to 1.8 with their trades unaltered. If a villager hasn't been loaded for a certain amount of time (unknown set of time as yet) in 1.7 the villager will be automatically converted to a 1.8 villager (similar to water temple retro generating.) If the villager has been loaded long enough the trades will be untouched and the new 1.8 trades will be added on to the end. This mechanic allows for certain trade hunting in 1.7 ex. book trades and enchanted tool trades. It is very handy to spend time working on this as you can get duplicate trades like iron, wheat, paper, or coal for less emerald spendage.
Trading Tools Edit
To manage the big amount of villagers 1.8+ Book Trading can cause this Spreadsheet will sort and compare them for you.