Mission discoveries for Diplomacy and Bioanalysis lowbie mats are very inexpensive. I find myself snatching a lot of these up and crafting purple lowbie implants, most of which sell from 15-25k easily. I'll usually net around 500k a week just selling implants.
Exotechs sell nicely, but with the rapid undercutting they're often listed below market price for the materials. In this case, it is more profitable to sell the mats alone or save the stims for an opportune time to sell them.
If you find the mats yourself it is like 4-5 times cheaper than to buy. The people undercutting are the ones who can afford to due to this. I make 250k a day just on stims. People have to buy them over and over. Implants are a one time purchase. With a business model like that, you would be eaten alive on dragons den/shark tank.