Magnets

Magnets are the second resource you'll get in Scrap 2. They are important in the beginning, and even more later. With them you can buy six Upgrades (ordered from most to least important):

Upgrades
Faster Level Up (max level 20): reduces about 1.6 Merges per level, up to about 32 merges at max level. This is very important because this will be your main magnet income.

More Golden Scrap (max level 40): Gives +5% per each level. It is important to maximise GS (Golden Scrap) income to get Stars faster, even though it get expensive.

Better Boost (max level 50): Gives +1% per each level to the bonus each GS gives. At the beginning level 9 is more than enough.

Offline Production (max level 20): Gives +30 min to max Offline Production per level.

Better Storms (max level 10): Reduces 6 seconds per level between Storms. This won't give you many magnets, but in the future will be better.

IMPORTANT: Try to upgrade every of them to max before 10 Stars.

In the future you'll use them to upgrade Stars.