The base game is priced around 40 dollars with occasional discounts.
Each expansion pack averages 40 dollars while game packs and stuff packs cost 20 to 25 dollars each.
There are more than 20 packs so buying everything at full price totals over 500 dollars.
EA frequently runs sales offering 50 to 75 percent off older packs which lowers total cost significantly.
Optional bundles like the Premium Edition often include 2 to 3 expansions at a reduced price.
Sales during holidays or Steam/GOG events are your best chance to get full content cheaper.