This is the way.
Warbond Nova Tonk ccu saves you $15
Warbond Ares ccu saves you $20
Warbond Harbinger ccu saves you $20
Warbond C2 ccu saves you $40
Warbond M2 ccu saves you $40
Nomad has $80 upgrade value. With 6 days left you are at $115 in savings from sale.
In addition to what Doyzer said you can also buy intermediate CCU of ships not yet released, when available.
It's longtime planning (between this ILW and next IAE and Alien week).
But if you missed the warbond mentioned above as some were available just for one day this event, you can take some of those store credit CCU, some are already available this sale.
This is also a game of patience since you will need all ships mentioned in those CCU to be released, and then complete the upgrade path.
Nomad to Hull-B
Freelancer DUR to Vulture
Vulture to Taurus or SRV
Hurricane to Vulcan
Vulcan to Corsair
Corsair to Scorpius/Ares/Santokyai
Scorpius/Ares/Santokyai to Apollo Triage
Apollo Triage to Appolo Medivac
Starfarer Gemini to Crucible/Endeavor/Hull-D
Crucible/Endeavor/Hull-D to Genesis Starliner
Prowler to Banu Merchantman
??? to Carrack (can be BMM when released or M2 if you took the warbond CCU).
Considering current price jumps rates this will save you probably above 200$