Enchanting materials used in this guide:
- [Large Brilliant Shard]
- [Greater Eternal Essence]
- [Arcane Dust]
- [Illusion Dust]
- [Greater Planar Essence]
- [Large Prismatic Shard]
For assistance with finding items that will most often give you the materials you are seeking, check out Wowwiki's disenchanting tables
I'll try to avoid recipes that cannot be obtained from your trainer, and include any exceptions at the end. 300-301
While these are not as cheap, they are alternatives if the market for these enchants is higher. You could also request that people provide their own materials, making it no more expensive for you.
At this point, you'll hit the wall and have to start relying on faction reputation. The easiest thing to do will be to use whatever faction you already have to the necessary reputation. Consortium: 365-375
Cenarion Expedition: 365-375
Shattered Sun: 360-375
Tips and tricks
While the above may be the cheapest method on paper, you're likely to stumble upon a bit of luck in some form or another. Maybe a very popular recipe drops for you, or is given to you by a guildmate. Perhaps your guild provides a market for your services, or you find that your connections on the server seem to bring you business.
By all means, take advantage of requests from friends, solicitors in trade channel, tips, and free things in order to advance your career and build your skills. Deviate from this guide if you stand to make money, or even a valuable contact and a better reputation.
In addition, you can disenchant everything you can get your hands, or paws, on, from quest rewards to dropped items, to crafted items. You may end up with more materials than you need, allowing you to make a profit, or at least recover some of your losses.
You might want to try advertising enchants for free with the client's materials. Often you will be tipped anyway, and even if you are not, you are earning skill points for free, and selling all of your materials on the auction house.
Finally, if you yourself need an enchant, no matter how expensive, then you might as well milk a skill point out of something you intend to do anyway.