I picked up Steam Puppy for $5 on sale and it got me to VIP3, that was the best progression I got thus far in-game. It also gave pet tiers up to the orb.
They’ve removed the $5 traitstone bundle that counted as a $25-30 purchase as well on mobile but that was worthwhile for VIP tiers.
The flash offers for old event weapons are a great deal if you want the weapon, but I can’t remember offhand how many VIP points it gives you. Not a lot, but it stacks up and I was able to grab a Doomed Blade off of one and effectively save myself a year of waiting for it to show up in the forge (it still hasn’t shown up since I started playing, here’s hoping Monday’s offer is the Doomed Scythe so I have the full collection). I also usually pick up the vault keys, not a lot of points but they also add up and are decent little gem/growth orb bundles.
If you’re feeling especially spendy, the Deathknight armor stays valuable the longest.