Michael Fletcher 36's page

The 4k cost is disproportionately small for practically eliminating the detriments of wearing armor.

While I would personally feel that you could have your Mithral Celestial Armor, it would not be a simple 4k increase.

Let's just say it takes a lot more effort to make those links that "fine" to gain all the mechanical benefits that create "celestial armor."

Price? Probably 36,000 gp. That's the cost of Mithral x (the number of times you benefit from Mithral) squared.

But... that's just my opinion. You and your GM should hammer it out due to the existence of existing custom items in the game. If you're wielding the equivalent of ~+7-+8 custom weapon, you shouldn't have issues with a 36k armor enhancement.

One thing to note, however, is that this typically entails the abuse of inordinately powerful spells, for little to no cost, which are included to increase the survival of low level casters.

Some additional rulings you might want to consider:

If the spell can't be made into a consumable item and/or you can't cast the spell on someone else, or an item already exists (but might not be as good), then it probably shouldn't exist. (Shield comes to mind.)

If the spell does not thematically fit, then it probably shouldn't exist. (Barkskin on hulking armored warrior comes to mind.)

A similar concern is sinking funds into permanency.

Roll an intelligence check for random information. If it falls within the realm of a knowledge check, have them roll that, instead.

If the information is key to continue with the game, and they fail horribly, be vague. Other players (or NPCs) can assist, as needed. If they roll well, simply tell them. In either case, roll a d20 for appearances.

If the information is not key, DM rolls a d20, and adds the appropriate DC modifier.

-25 (If today is your anniversary, if female)
-20 (You're staring at the readily apparent answer)
-15 (Your name)
-10 (Your birthday)
-5 (What you ate for breakfast)
+0 (What you ate for dinner two nights ago)
+5 (Your girlfriend's mother's birthday)
+10 (Your entire family tree for the past 100 years, as told in the form of stories from your grandfather when you were a child)
+15 (How many gold pieces you spent in the past year)
+20 (The number of steps on the stairs you were fleeing down after you were found by the bonny princess' personal guards in her bedchambers last night)
+25 (If today is your anniversary, if male)

Note, additional modifiers as warranted.
Under the effects of alcohol: Number of drinks squared divided by three, rounded down (1 -> 0, 2-> +1, 3-> +3, 4-> +5, 5 -> +8, 6-> +11)

Blunt trauma to the head, cumulative d20-10. (Multiple strikes result in intelligence, wisdom, and charisma drain.)

It's most definitely allowable as far as I'm concerned.

Liquid Methane, whilst boiling at a warm -100 some-odd Centigrade, can support a pool fire.

Go ahead. Stick your hand in. See if your hand doesn't frostbite, while your clothes are set on fire.