Okay. I decided to pick up engineering, Here's the guide that I created last night, trying to spend the least amount of gold I could. I must admit that it's about 70 gold for EVERYthing, But in the end, you'll have like 20-25 gold in your pocket. This is the Quick and Dirty way. If you can't keep up with the bill, I suggest getting mining, as it alleviates nearly 90% of your costs when you just straight mine to 300.
First is the shopping list of all items I used in my powerlevel. You WILL have leftovers on most things but I padded for the unlucky.
Next is the List itself. What to skill up on until the level desired. For instance, 1-40 means stop doing it when you get your 40th profession point. Next, what typically you can do with the item. Then, AHed ingredients and finally the ingredients in ONE make of the crafted item.

Also, please leave comments.

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Shopping list of items needed:

90 Rough Stones (AH)
80 Coarse Stones(AH)
70 Heavy Stones(AH)
60 Solid Stones(AH)
50 Dense Stones(AH)
10 Wooden Stock (EVend)
29 Weak Flux (EVend)
50 Heavy Leather(AH)
10 Wool Cloth (AH)
33 Runecloth(AH)
51 Copper Bars(AH)
10 Silver Bars(AH)
55 Bronze Bars(AH)
15(*19) Iron Bars(AH)
*4 Coal (EVend)
4 Steel Bars (*get a blacksmith to make from iron and coal, MUCH cheaper.)
106 Mithril Bars *cringes, sorry.*(AH)
159 Thorium Bars *runs*(AH)
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Engineering trainers are usually found in major cities.
Artisan engineers can be found in Orgrimmar and Ironforge.
The single master engineer (for all engineers) can be found in Gadgetzan in Tanaris. His name is
Buzzek Bracketswing.

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Level: Name of Skill, approx to keep. Keep more in case. [how many to buy from AH.] (recipe req. for each.)

0: Buy a Blacksmith hammer.
Buy Schematic: Green/Blue/Red Firework (Fireworks Merchant in Booty Buy/Iron Forge/Orgrimmar) 40s
Buy Schematic: Thorium Widget - Engineering Supplies in Orgrimmar/Ironforge 1g
Buy Schematic: Thorium Tube - Engineering Supplies in Winterspring (Everlook) 1g40s
1-40: Rough Blasting Powder, sell all [90 Rough Stones] (1xRough Stone)
41-50: Handful of Copper Bolt, used for 66-75.[10 Copper Bars] (1xCopper Bar)
51:Arclite Spanner
[6xCopper Bar](6xCopper Bar)
52-65: Copper Tubes, 10 used for 66-75.
[35 Copper Bars] (2x Copper Bar 1x Weak Flux)
66-75: Rough Boom Sticks, sell all (
[](1x Copper Tube 1x Handful of Copper Bolts 1x Wooden Stock)
76-95: Coarse Blasting Powder, keep 20 for 121-125.
[80 Coarse Stones] (1x Coarse Stone)
96-105: Silver Contacts, Keep 5 for 146-150, Keep 5 for 191-195.
[10 Silver Bars](1x Silver Bar)
106-120: Bronze Tubes, sell all.
[30 Bronze Bars](2x Bronze Bar 1x Weak Flux)
121-125: Small Bronze Bombs, sell all.
[10 Bronze Bars, 10 Wool Cloth]
(1x wool cloth 1x silver contact 4x coarse blasting powder 2x bronze bar)
126-145: Heavy Blasting Powder, 10 for 146-150, 50 for 150-175, 15 for 191-195.
[70 Heavy Stones] (1x Heavy Stone)
146-150: Big Bronze Bombs, throw at friends or sell.
[15 Bronze Bars]
(2x Heavy Blasting Powder 3x Bronze Bar 1x Silver Contact)
150-175: Blue, Green or Red Fireworks, sell.
[50 Heavy Leather]
(1x Heavy Leather 1x Heavy Blasting Powder)
176: Gyromatic Micro-Adjustor
[4x Steel Bars](4x Steel Bar)
177-190: Solid Blasting Powder, 10:206-210, 15:211-225, 16:236-245, 10:246-250
[66 Solid Stones](2x Solid Stone)
191-195: Big Iron Bomb, sell
[15 Iron Bars]
(3x Iron Bar 3x Heavy Blasting Powder 1x Silver Contact)
196-205: Mithril Tubes, sell.
[30 Mithril Bars](3x Mithril Bar)
206-210: Unstable Triggers, 10 for 236-245.
[10 Mithril Bars, 10 Solid Blasting Powder]
(1x Mithril Bar 1x Mageweave Cloth 1x Solid Blasting Powder)(need for later)
211-225: Hi-Impact Mithril Slugs, sell on AH for good profit
[15 Mithril Bars, 15 Solid Blasting Powder]
(1x Mithril Bar 1x Solid Blasting Powder)

---From here, the going will be dangerous, you may want to stock 5-10 more of each thing I've listed in case of TERRIBLE steaks of luck, as you will be flying out to Gadgetzan. Also see my section below about Goblin/Gnome engineering. That is an expensive way to level, and my FAQ is cheapest without having to make a choice.---

226-235: Mithril Casings, 10 for 236-245.
[40 Mithril Bars] (3x Mithril Bar)
236-245: Hi-Explosive Bomb, sell.
[10 Mithril Casings, 10 Solid Blasting Powder]
(2x Mithril Casings 1x Unstable Trigger 2x Solid Blasting Powder)
246-250: Mithril Gyro-Shot, sell.
[16 Mithril Bars, 16 Solid Blasting Powder]
(2x Mithril Bar 2x Solid Blasting Powder)
251-260: Dense Blasting Powder, Keep all for shells!!
[50 Dense Stones](2x Dense Stone)
261-290: Thorium Widget, keep for most high-end stuff or sell.
[99 Thorium Bars, 33 runecloth] (3x Thorium Bar 1x Runecloth)
290-300: Thorium Tubes, keep for most high-end stuff or sell.
[60 Thorium Bars] (6x Thorium Bar)
---When all is said and done, it should have taken you 3-5 hours to get it all made. Grats