Sales

im holding out in case ex passes make its way into the store

If you can hold until gen 3 (whenever that be) it is the biggest chance for storage sale.

For Gen 2, they gave 50% Pokemon storage. Saving my coins in case they do it again.

There's never been a sale on item storage, but they had Christmas Box sales last year with discount stuff too.

Bottom line: If you don't need it immediately, might as well wait.

Since 500 seems to be enough storage space for me for 2 generations, so I plan to get 250 more when Gen 3 comes out. Assuming a sale to 100 coins per 50, I'll need 500 coins for storage. I am keeping that as a minimum for the time being (free to play player).

I wouldn't be surprised if we get a sale/special boxes for most of the major(ish) events. I personally like to bank about enough coins for 8 incubators, since I like to hold on to my 10ks until I have 9 and then hatch them all at once. When I go over that much, I will buy more storage upgrades whether I think I need them or not, I've now currently maxed both and may switch to buying additional premium raid passes, or just stockpile them in case incubators go on sale.

If that is your top priority, I would wait another month or two and see what happens with storage for Gen 3. Hopefully they don’t wait too long after the Halloween event to release the rest of Gen 3.