Hey guys, posting a compilation of what has worked for me in the engineering market. It goes in order of profits, from best selling to lowest. remember, this is what I find the best to sell, it may fluctuate on your server.
Smoke flares. these are good for just about anything, but mainly fun and communication.
1. Purple smoke flare (rare schematic from BC zones. picked my schematic up for 2k, have made about 10k profit)
2. Green smoke flare (hyjal rep reward, friendly required)
3. White smoke flare (sold by various engineering supplies vendors in outland)
I usually can sell smoke flare stacks from 100g a stack to 80g at lowest. you need to advertise these in trade, as most people do not see them on the auction house. The mats are cheap, and easy to get yourself.
Pets. now, the easy to acquire pets are hard to sell. but if you can find the rare
schematic ones, prepare to make a payload!
1. Lifelike Mechanical Toad is a huge seller, often netting 200-300g a piece. I got my schematic from a world dragon, and the only known boss to have a higher than 1% drop chance is old nefarian. goodluck grabbing this schematic.
2. Pet bombling and lil' smokey are two pet schematics found in gnomeregan. both schematics are bop, but the pets go for about 80-120g each.
3. Life-like mechanical yeti is a quest reward in winterspring. prepare to net about 100g from each one.
4. the trainer taught pets do not sell well for their mat cost, I do not advise selling them.
Misc items that sell well.
Voice amplification Modulator- reduces stun and silence effects by 10%, counts as a neck slot item. this sucker is craved by twinks under lvl 40, and sells for me regularly at 200g.
Gnomish army knife- an all in one trade item, containing things like blacksmith hammers and mining picks. about 50g a piece on my server, easy to make.
Ornate spyglass- a fun item that increases seeing distance. cheap to make, sells for 75 a piece on my server.
Crashin thrashin robot- expensive to make, so dont bulk on them. I usually get 100g profit on each one.
of course, the chopper/hog.
Lastly, some engineers may not have a rare schematic you have. things like the gnomish cloaking device will sell as well to engineers too lazy to research where to get it.
Wrap up:
I usually can make about 5000g a week from engineering, but this isn't my main income. the main cash flow is smoke flares and the rare pets. Good luck fellow engineers, and don't forget to advertise in trade!