This guide is thought to be for new accounts. We start with rebels because those have multiple purposes, e.g. Lando and STH are scoundrels you need for events, Wedge and Biggs are good pilots, and fiv...
Back to @Malicious question what to buy. Here @Tiggus made an interesting list: https://docs.google.com/spreadsheets/d/1G7fRR1taw83uBzsh5Ss9LDNqHXplvDK4cHZ6pBQ4jns/edit#gid=1679694163
After studying the list, I went to my guild store and bought a Bacta Gel Mk2 proto :)