With the NEXT update, I have found a few ways to make units quickly or at least in large amounts at a time.
Your multitool's scanner without any kind of upgrade is quite a poor way to make units. However, I've managed to obtain an upgrade that I purchased from the store in a space station that provides the following bonuses:
Yes it is an S class upgrade, and yes, I may have gotten lucky with what this technology does, but as you can see, I get a 6512% unit increase for all fauna that I scan (animals), and a 9321% unit increase for all flora I scan (plants). For all of the plants I scan, I get 23,817 units each. Most planets have an abundance of flora to scan, making it quite easy and quick to make some units. As for fauna, depending on how rare they are, I can make anywhere from 30,000 units to just over 100,000 units per fauna scanned.
Exploring Ancient Ruins
This is one of the more fun ways that I've found to make units. You can also go about finding Ancient Ruins in multiple ways. The first time I found an Ancient Ruin, I asked a Gek for directions (which is one of the dialogue options when speaking to most aliens in the game), and the Gek pointed me towards an Ancient Ruin. At this Ancient Ruin, I interacted with the object that was there (I'm not sure of the actual name of the object). It provided me with two options - seek language help, or seek knowledge of the past. Select the seek knowledge of the past option, and it will point you to another ancient ruin, only this time it should be one that is buried under some terrain.
After you reach the next Ancient Ruin, start digging using a terrain manipulator. Dig near the pieces of the ruins that are sticking out of the ground to find these small chests. These chest contain "Ancient Keys." You will need to find at least three of them, though I believe the ruins contains more than three to find. After finding three of the keys, dig near the center of all of the ruins. You will find a large chest that will require three ancient keys to open. Once you open it, you will find a random ancient artifact item, that is usually worth a lot of units. The first time I did this, my artifact fetched me over one million units.
I believe another way to find these ruins is to use your signal scanner and a Navigation Data chip on it, and select the Scan for Artifacts option. This will lead you through the same process.
As a side note, I believe these ruins always have two Gravatino Balls to be found (one is on a ramp of one of the ruins, while the other may be buried). These are a way to make a quick buck, but picking them up will always trigger the sentinels to attack you, so it may not be worth it.
Crafting Frigate Fuel
After obtaining a freighter, and going through the short tutorial with it, you can craft some Frigate Fuel. This recipe is quite simple to craft as well. All you need is Di-Hydrogen, and Tritium. Di-Hydrogen I've found on every planet I've been to so far. It looks like blue crystals that stick out of the ground. Tritium is quite commonly obtained by destroying asteroids when flying around a solar system. Frigate fuel can be made in the following quantities:
- 50 Tonnes - requires 50 Di-Hydrogen and Tritium
- 100 Tonnes - requires 100 Di-Hydrogen and Tritium
- 200 Tonnes - requires 200 Di-Hydrogen and Tritium
Each of these are worth around 1000 times their weight in Tonnes (50,000, 100,000, and 200,000 units respectively). Depending on the Market, you can get a little more, or possibly a little less that what the fuel is worth.