SI40 Making
Si40s can be an insanely expensive investment, but unfortunately, some heroes require it. The 305 reds/380 whites I would only ever recommend to people who were around for the si40 release and, as such, have received ~2,000 free white chests.
The 405 red cost investment is what most people will be able to do (pre-reso 18), and the 495 reds cost is probably the best one with our current income for post-reso 18 players.
I'm setting pet reso 18 players aside from the rest because they can take red chests from every source instead of being locked into taking bait.