What do I really need to buy?

Hint 1 of 5:

You will find some items throughout the game as you go, so not everything
must be purchased here.

Hint 2 of 5:

You will need the Portable Smelter.

Hint 3 of 5:

You will need Thermal Mittens.

Hint 4 of 5:

You will need the SynSkin gloves (at least one pair).

Hint 5 of 5:

You will need the Rock Cop.  It will help you identify precious and
semiprecious gems as you begin your mining activities.