Do you pay for R'lyeh prophets?

[Illuminated One]

I.e. if someone goes mad and makes himself a prophet do you pay upkeep for him or is only your real (who was that againg...?) prophet free

[Squirrelloid]

They do receive the sacred flag (if they didn't already have it), so at the very least their upkeep should be reduced like any other sacred.

And most of the time those prophets will be your freespawn commander units - now, its hard to tell given how much freespawn you can get in a turn, but i'd guess at least the aquatic ones don't cost any upkeep normally (deep one looking ones) because you can't otherwise buy said unit. Testing this would be rather hard, however, unless someone who has modded the game knows if the freespawn commander has a cost associated. Anyway, if he's free normally, he's still free when he's a prophet.

[Endoperez]

They do receive the sacred flag (if they didn't already have it), so at the very least their upkeep should be reduced like any other sacred.

And most of the time those prophets will be your freespawn commander units - now, its hard to tell given how much freespawn you can get in a turn, but i'd guess at least the aquatic ones don't cost any upkeep normally (deep one looking ones) because you can't otherwise buy said unit. Testing this would be rather hard, however, unless someone who has modded the game knows if the freespawn commander has a cost associated. Anyway, if he's free normally, he's still free when he's a prophet.

Edi's Database lists all units' gold costs, or lack thereof.

[Illuminated One]

Well, they don't get the sacred but the blessed tag, which doesn't automatically mean it affects their cost (like with shrouds).