- 60 Crystals from completing all Dailies.
- If you are 85 you get a price box that can give 5-10-50-100 crystals (most of the time 5-10, it probably averages at 14, 15 overall)
- 25 from completing Galactic War. (5-5-5-10)
- 300 Crystals from Daily Log in over a month (~10/Day)
Overall without even entering Arena if you complete Daily stuff you get at least 95 Crystals / Day in the long run (110'ish if you are 85)
I don't know your Arena Rank but 150 seemed a little too few to me, you are probably getting more than you realize.
Either way, refreshing Normal and Cantina Energy gives you a lot in the long run, I advice players in my Guild to refresh them depending on their Crystal gains, and to gather any and all other Crystal to buy Raid only gear from Shipments.
For example: If someone gains 190-200 per day, 1 Cantina + 1 normal energy refresh and gather the 40-50 for buying Raid only gear from Shipments. (Most often than not that 40-50 extra becomes much more due to Daily Login rewards and extra 50-100 crystal drops from 85 Price Box and it really adds up to 1400 easily) You just need to be patient.
Also if you watch the meta carefully beforehand, and make the right choices before it even happens, you can easily increase your Arena Ranking.
F2P here and ranking top 1-2 everyday on Arena (with an occasional 4-5 depending on luck), against 7* Jyn/Chaze/Cassian whales. So yeah, it's indeed possible, with a little bit of luck and smart play.