Mounts are the thing that makes your whole life much much easier.At level 40 you can acquire em buy buying the training and a mount,altogether costs 100g.I suggest farming for it.Pallies and Loks get a quest for them so its much easier hehe.You must also be exalted with other factions to be able to buy them.Stormwind has horse mounts,Ironforge has Yak mounts,Gnomes have chicken mounts,Night elfs have Tiger mounts,and Draenia have Elk Mounts.Lets review on how to get them
- Must be level 40
- Must have 100g
- Must be exalted with the faction
- Pallies and Warlocks get free mounts,just have to do the quest
At level 60 you get an epic mount.Costs 630g.Pallies and Warlocks get free mounts but must do a difficult quest. You must be exalted and choose wisely.Pallies and Loks get a specific looking mount.
- Must be level 60
- Must have 400g
- Must be exalted with faction
- Pallies and Warlocks get a free mount but must do a difficult quest
Here is a picture of all the mounts

The Horde and Alliance have different looking mounts.
Flying Mounts are acquired at level 70 and you must have Burning Crusade.They cost 800g and cannot be acquired in quests.They make travel in outlands much easier.
- Must be level 70
- Must have Burning Crusade to get to level 70
- Must have 1100g
- Cannot be acquired by mean of quests
- Epic Flying Mounts are 5200g
Heres a picture of a flying mount

Again,Horde and Alliance have different flying mounts
As you can see,it takes a long time and work to get mounts,but its worth it.Good Luck!!!!