Hang around the Ebon Hawk for a bit and talk to your party members. Some of them will produce items to prepare you for upcoming missions, as noted below.

Mission - Security Tunneler Spikes
T3-M4 - Computer Spikes
Canderous - Adrenal Stimulants (Strength, Alacrity, Stamina randomly)
Zalbarr - Grenades (various types)

Check with those party members (and others) to see what all is available. You can talk to those party members regularly to get additional supplies, until you are carrying a set number. When you run into the limit, you can then deposit your loot in the cargo room containers and talk to your party members again to convince them to make still more goodies for you. Then, when you happen across a vendor, you can sell any excess goods and use that income to invest in other items of interest to give yourself a real boost.