Any advice on what to purchase first in terms of powerups / abilities?

[Corinthas]

I have just arrived at the spacestation and saved for the first time. Before i go back down to the planet, is there anthing i should buy that will be helpful?

[Scorpix]

Fishing and Sound OS :D

Buy some recovery. Save your cash to get more space for chips, which you will be able to buy in the Resistance Camp.

[Litzor]

Get all of the storage upgrades for your plug-in chips ASAP. Then spend money on fusing chips/upgrading weapons. Ideally, you want to fuse chips that have the black diamond next to their name as they take up the smallest amount of storage space. Buy recovery items as you need them. Money isn't too hard to come by in this game, at some point in my first playthrough I just bought 99 of each Recovery item.