This trick can be done starting from Assignment 4. Just follow a few simple steps. This is modified from Illusionbreaker's topic on GFAQs.

  • (Liquid) x2

    • Make two Leathers. The first is made with Soft Leather (High Price), and the second with Quality Fur (High Price+).
    • Make a Distilled Water using a Silver Hive (High Price++) and Leather (High Price+). Use Division on Silver Hive. Keep Rare Goods and High Price++.
    • Make a Mixed Lubricant using two Leathers with High Price and High Price+, keep High Class Item.
  • Purple Crystal

    • You will need the LV2 properties from both upcoming items. Not too difficult. Without either, you will not be able to afford High Price++.
    • Make a Crystal Ball using the Mixed Lubricant. Keep High Class Item and Inherit PP +3.
    • Make a Purple Crystal using that Crystal Ball and the Distilled Water. Use Division on the Distilled Water. You will probably need to use CP Recovery to do this. Keep Premium Price, Rare Goods, High Price++.
      • So why use Division on that water? You want its properties to be included twice. Use the system's quirks in your favor!

Enjoy. You'll want to get your Homunculi duplicating this in their spare moments so you can afford all the experiments. It's better to put one crystal per slot as opposed to multiple crystals in one slot. At max Effect, I was selling these for 4620 each.

As for experiments, I'd prioritize storage and time savers, then combat related stuff, then alchemy stuff. Oh, and be sure to squeeze in Homonculi experiments from time to time.