I don't really think the time to get more coins should be shortened. I mean, it's annoying enough to travel to Aven every two hours to get a chest. But to cut that time in half? Bleh.
As for pricing suggestions, perhaps a hour to hour exp boost would work out.
Auric Jewl=7 Day worth of Bonus Exp.
Let's go with playing an average of 10 hours a day (this includes afk time seeing as that count towards getting more coins). So 10 hours a day for 7 days would be 70 hours. In this case, I think 70 coins would be pretty fair. Any lower, there won't be a single player playing online anymore that doesn't have an Auric Jewel on.
Exp Charm I think about 8-10 coins would be good. One day= One exp charm.
World Calls... Will people actually buy these? o,o Maybe in Emergencies... So one coin o,o
As for what to add to the shop, you should add a mount for like 599 coins.
Makes people save up coins, wanting to use them, but also wanting to save for mount. It's brilliant