Please help me understand the economy

I've been totally ignoring my rewards and just grinding XP, but I figure at some point I'll need to understand and optimize my consumable resources.  From what I can gleam:

• "Coins" are the in-game exchange for real-world cash; they can be converted into other resources
• "Wildcards" have a corresponding rarity and can be converted into any desired card of that same rarity
• "Expedition Tokens" can be redeemed for 3 Expeditions runs, which in turn reward shards, wildcards, and random cards
• "Shards" are the baseline currency which can be converted into Wildcards and/or Expedition Tokens.

Is that all of it?  Are "capsules" not a thing any more?

Coins are purchased with cash. Apart from cosmetic items, your ability to spend coins in the game is very limited, with a weekly reset. You may use them to purchase up to 3 Champions, 3 epics, 6 rares and 6 commons per week, plus expedition tokens (of which you can use only 2 or three per week).

Wildcards are exactly as you said: You used them to craft a card of the given rarity, on a 1-1 basis.

Each Expedition Token will get you one expedition run, consisting of two trials (i.e. separate drafts). Each trial lasts up to seven wins or two consecutive losses, whichever comes first (though you do not get a second chance at the final battle). Each trial grants an XP bonus upon completion (up to 2000 XP for seven wins), so it's important to do your best on both trials. Your first three Expeditions also grant card and shard rewards based on the completed trial with the better record; the worse trial doesn't figure in at all for this part of the reward. This final reward always includes a random Champion.

After three Expeditions in one week, further Expeditions are free to enter, but they are only one trial apiece and there are no card or shard rewards. You simply get the normal trial completion XP bonus based on your number of wins.

Shards can come from chests or from receiving a fourth copy of a common or rare. (Extras are converted automatically; you can never actually own more than three copies of anything.) Shards can be spent to craft any card or to enter an Expedition.

Note also that random card rewards of epic or Champion rarity will never be a fourth copy. You will always get something you didn't have three of.

Also, the shard price to craft a Champion is 3000, the same as the price to enter an Expedition (up to three Expeditions per week). The deciding factor here is: Do you need a specific Champion, or are you content with a random one plus the additional Expedition rewards? In the long run, Expeditions are more economical than spending your shards on Champions directly, but in the short term, your decks will be better if you craft what you actually need.

Choose the reward region for levels of 4. Getting the wild capsule rewards is pretty good. Rinse snd repeat for each region.

Quote From FortyDust

Note also that random card rewards of epic or Champion rarity will never be a fourth copy. You will always get something you didn't have three of.

Could you share where you learned this? Because this is awesome if it is true.

Edit: Just found it here (yay it's real!): https://support-legendsofruneterra.riotgames.com/hc/en-us/articles/360035570054-Duplicate-Protection-and-Shard-Conversion-in-Legends-of-Runeterra

And when does the week for three expeditions reset? On tuesday?

Quote From Smradd

And when does the week for three expeditions reset? On tuesday?

Yes. on tuesdays. I'm in GMT +3, it was on 5:50 AM.