Garrisons are the best, main, and easiest way (not cheap though) to make gold in WoW with the expansion WoD coming out. Garrisons cost around 50,000 to get running meaning that it's level 3 and most buildings are at level 3. This is a rough estimate but the blueprints cost lots of money to get set up. Garrisons are fairly simple to maintain and take about 1 hour to finish all the daily stuff such as the mine, herb garden, profession buildings and more! In the following I will show ideas and suggestions for what buildings are most profitable and are easy to maintain. Garrison buildings are easy and an excellent way to make money however you need to get money to start out with. It's going to cost allot of gold starting out but after a while you're going to love how much gold it makes after a couple of days. Now I will show the Small, Medium, & Large buildings and which ones I think are the most profitable along with some other buildings.
Garrison Missions are extremely profitable. Go for the garrison missions that reward gold, then epic gear, then garrison resources, then gear upgrades then anything else. Garrison resources can be turned in for the materials to sell, gold output from the missions can be doubled and tripled, epic gear sells for lots of gold, and gear upgrades sell for gold.
Herb Garden is wonderful especially for those of us who have professions that use herbs. If you don't have a profession that uses herbs then just sell them. WoD herbs are going for around 1 or lessright now.
Garrison Mine is helpful for those of us who have a profession that uses ore. If you do not have a profession that uses ore just sell them. Currently ore is going for around 3 each and can go up and down by 1 each.
Small buildings are the best next to Medium buildings. You can have three Small buildings. In the following I will show what I think will make the most gold and what I use usually.
Make two profession buildings that match your profession. Profession buildings that match your profession make the most gold together. It's the easiest to do. Also it's helpful and provides more materials then the profession by itself.
Storehouse. The Storehouse is amazing, it provides more slots for your garrison buildings and gives you a void storage, bank, transmogrifier, & guild bank. It's an amazing addition to your garrison and is very helpful.
Medium buildings are the best ever. It's a really really hard decision choosing which buildings to go for, however I chose the following that would grant the most gold.
Barns is the wonderful for making gold. You can make money with the barn by selling the furs, leathers, and savage bloods. Furs can sell for around 2 each, leathers sell for around 3 each, and savage bloods sell for around 150 each.
Trading post is the best medium gold making building. Garrison resources are traded for common WoD materials. The best one that sells is the Draenic Dust. Draenic Dustsells for around 3 each! It's the best selling material on the market right now besides selling fish. Speaking of fish, fish sells for lots of gold too. So basically check your AH for what sells best then trade in your extra garrison resources for those materials and sell them! It's extremely easy and profitable.
In Large buildings there are almost no profit. However I will list what buildings I think are interesting and are kinda cool. You can have two garrison buildings in the Large size.
Stables is pretty awesome. It provides 6 mounts after about one month! They look pretty cool too! I'd go for stables because I love mounts and it's a nice building. It also shows off random mounts in your pet journal so it's nice if you want to show off your mounts in your stables.
Spirit Lodge I would not go for. However, I play a mage so there isn't any need for the Spirit Lodge. For other classes though this is extremely helpful especially if you do battle pet trainers around Draenor. You can only have two buildings of the Large size but I'm going to show a substitute for the Spirit Lodge.
Barracks is just fun. At level three you get banners, specialty guards. which is fun! This is purely for vanity but I like it.