Mod Store: I'm not going to go into Mod strategy. That's a whole other thing, and it wasn't listed in your priorities, so I'm going to let you read tutorials on mods, mod farming, and mod purchasing elsewhere on the internet.
Guild Events Store: This is effectively 2 different stores because there are 2 different currencies. They are generally referred to as GET-1 (or just GET1) and GET-2 (or GET2). For no particular reason, the GET-2 purchases are all at the top, so we'll address those first.
GET-2 Purchases: 1. Malevolence => 7*
2. Negotiator => 7*
That should keep you busy for a good, long time.
GET-1 Purchases:
Hermit Yoda => 7*
Save 40,000
Question: Are you ready to pursue Malak yet? If yes, then keep saving. You need 65k or so for Malak. If no, Wampa => 5* right now.
When Malak is unlocked using his event (which gives you a 5* Malak) => 7*
Wampa => 5* if not done earlier.
Save 65,000 for General Skywalker
Anything over 65,000 can be used to bring Wampa => 7*
Now you can begin purchasing gear
That should also keep you busy for a good, long time.
Championship Store:
Purchase top row gear only, except in an emergency.
In emergencies, purchase Kyrotech Shock Prods or Kyrotech Battle Computers.
Shard Store:
Save 2,000 currency that you use ONLY for MK5 Stun Gun Salvage
Purchase every Mk5 Stun Gun salvage you find here. They only appear on the 4th row, in the right-hand slot.
Use currency above your 2k limit on 2nd-row right, 3rd-row left, and 3rd-row middle gear.
All of these gear types will be 360 currency per lot, and each lot will contain 4 salvage. If you're not buying Mk5 Stun Guns for 372 currency or the gear for 360 currency, you shouldn't be buying that gear.