What have you done/are you planning to do with stardust from this event?
So far I've powered up:
1: Maxed a 14/15/12 Alolan Eggy from L30 to L40. 150k dust. I use him in every Kyogre raid where Cloyster isn't auto selected. May see some use against Groudon, especially solar beam.
2: Powered up a 15/13/15 shiny Lugia from L20 to L29.5. 70k dust. For potion efficient gym sweeping, especially for gym badge points.
Plans:
1: Power/max out a second Kyogre to around L35. Any weather boosted Kyogre with 15 attack will do. 106k dust.
2: Max out a Groudon. My current best one is 14/14/15 at L20. I'll wait for Groudon's likely return after Kyogre, to see if I get a better one. 225k dust.
3: Max out a 15/15/14 second Blissey. Currently at L37.5, CP 3101. Candy is the bigger issue for this one (but thankfully not too hard with field research and feeding chansey family in gyms). 47k dust.
4: Max out my first Snorlax. 14/08/01. Currently at L19, CP 1651. This one is more for fun and sentimental reasons, because of how I hunted for Snorlax like crazy in my first month or two of PoGo. This Snorlax also happens to have legacy Body Slam, so he will be a good gym defender.
Candy is the biggest issue here (I need 208 more candy to max it right now), and the only viable sources right now is buddying or feeding Snorlaxes in gyms. 234.4k dust. It will be expensive, but it's just a game, and what's wrong with maxing your favourite mons?
5: Smack Down Ttars. But this one can wait, they don't really have immediate use. I'll decide on the dust amount for this 4 hours later.
Over 612,400 dust needed for just these planned power ups. Should be doable by the end of this event, with some hard grinding. But again, candy/rare candy is the real issue for all 4.
Answers
1. Power up a second Kyogre. 145 -225k
2. Max my Mewtu, 10k (RC)
3. Max Metagross 96% plus IV 225k
4. Power up 4 SD Tyranitars, ~200k
5. Max Rayquaza, 80k (RC)
Kyogre will be leveled to 35,5 first and be maxed by the time we get a double candy for transferring pokemon if I catch one >96%. Currently my beat is a 15/11/15 and I already powered up a 15/12/14.
I'm just using it for the powerup quests and otherwise letting it accumulate, currently at a little bit over 3 million. Mostly maxing random perfect IV mon little by little and then moving on to the next one. Not much meta relevant stuff left that's not locked by candy.
Will for sure drop 268k on the 98% SD Tyranitar I'll have in a few hours, even if there's no immediate use for it.
If we get the Regis next, with Jynx back, I will spend nearly 100k dust each on a Moltres and Flareon. I will also invest in Articuno, as it is my team bird and my current ice attackers have bad moves.
Depending on which Tyranitars I power up, I will need between 230k and 310k dust for them.
As previously mentioned, I intend to spend 150k dust to turn two level 20 Chanseys (96% and 91%) into a level 30 Blissey (to eventually max out; another 150k) and a level 30 Chansey. However, if I keep doing Hatch 5 Eggs research to farm the Chansey candy that I need, there is a good chance that I may get a better Chansey.
P.S. Not likely that you will get a better Groudon.