Started playing at first release and gave up after a couple days. Just started back again and giving it a better try and here are my observations so far…
As a new player, you start with 100 amulets. In my opinion, use it to purchase a tier 3 character. They will have the best stats and will be able to let you get through most tier 2 levels pretty easily.
Whatever tiered level you’re doing has a chance to unlock characters from that tier. The game can get pretty tough when moving up to higher quest tiers so make sure your team is able to get through the current tier pretty easily before moving up.
Daily quests only give you 10 amulets a day. While there are quests that need amulets for each “try”, I’d suggest saving your amulets until you have a good pool of tier 3 and God characters.