First post here and I'm uncertain if this is the correct place to put this, but this seems like the best spot.

Anyways, I encountered an issue when I installed Tempest shortly after it went on sale with the release of Inferno. I normally play with a rather large map, mods, a custom faction, and high amounts of stragetic resources, luxury resources, and anomalies. Typically when I get the Altar of Auriga and I get the ability to pray I have a cost of 2 pearls on that very first turn prayer is available. This time however, it was 20 orbs on the first turn prayer was available. I've tested this a few times and the lowest I've gotten is 13 and the highest is 25. 25 on the first turn prayer is available is sort of ridiculous when I need pearls for other things and forces me to either abandon my current strategy or abandon Tempest, neither I really want to do. Is there someway to reduce the cost of prayer to what it normally is? Or is there a way for my orb collection to get drastically better?

Thanks in advance for any help!

Prayer cost is based not on the turn you build the Altar at. The lowest prayer cost is the first day of summer and then it goes up every turn.

Unless you're playing Allayi, pearls will be a secondary currency for you and obtaining them is largely just a matter of good scouting and map movement. Pearls appear every Winter (Dark Season) and the more armies you have moving around the map in different directions, the more of them you'll be able to collect each Winter season. Be wary of being caught unprepared because your armies are scattered and weakened but if you have good scouting and map awareness then you should be able to move about relatively freely. 

I also recommend upgrading your scouting units with the movement speed increase accessories as this will allow them to move around the map easier and if you can afford the vision increase accessories and/or empire plan then you'll spot pearls a lot more readily as well. 

If you want prayers and pearls to be a major part of your game play then I suggest obtaining an Allayi hero from the mercenary market early and level their faction tree to the skill that gives them more pearls and experience for gathering pearls, this will increase your pearl collection rate.