Years ago, I found a camp that we could use as a money farm, provided you met certain conditions. Here is the camp and the conditions to do them with. Being that the Heka Chests are no longer a thing, you can still use this money for upgrades and Tomes of Knowledge.
Dark Retro: https://youtube.com/channel/UCPUzTc1AMy4nopW85utYQAA
Dark Shadow: https://youtube.com/channel/UCQ0mAKCFqyfI_y0bESU1Sfg
Darkstrider Mobile!: https://www.youtube.com/channel/UC11CaJxbqP_O_8CTEhNZRhg
Join the Discord and help us out! : https://discord.gg/ppn4jaWZnP
Join this channel to get access to perks:
https://www.youtube.com/channel/UCP3VK2fBWLjXP3yg3Lyqe7Q/join