According to Major Nelson, EA Access (Xbox) will be worth 1/3rd per month of Game Pass Ultimate, so theoretically you can buy 12mth of EAA for A$37.19 and get 4mth of GPU for PC & Console.
I don't know when the cutoff will be for these, but if I get them I will probably hold on to the code until just before the inclusion date which is in 50 days.
CDKeys - A$37.19 EA Access
Kinguin - €20.85 (A$33.83) EA Access
BCDKey - A$31.93 EA 12mth
Xbox Live to Ultimate upgrade, if you have used it before it is A$15.95 to convert +1mth, otherwise it is A$1.00 for first time.