If you wanna take an unrealistic turn;
556 925 bones for 95, if starting at lvl 1, if using Gilded Alter with 2 burners
50m For 557k bones. - Not included cost of marrentills.
With XP/H peaking at 15k/h using normal bones on gilded alter, you would use approximately 585 Hours of constant praying on a gilded alter
So with 50m, it'd take about a month to get 95 prayer
Big bones would be twice as expensive, but also 3 times as fast.
Babydragon bones would be 3 times as expensive (as normal bones), but twice as fast as big bones. - 6 times faster than normal bones.
But I won't waste my time listing the rest of possible bones, but it WILL be expensive
