Alot of people were complaining that the prayers and items gods give you were not being given when you prayed to them. This is only because we based it on just prayer for a long time and hoping for the best. It isn't like that.
Every item (except Agenus' bow) and every prayer (Except Flaming Aura) has a low, medium, and high nest to their names, so in order to get them you need this amount of grace:
Low: 50 (100 with alter)
Med: 150 (300 with alter)
High: 300 (600 with alter)
The "with alter" part just means as you pray, your grace doubles, so in order to get thi particular item or prayer, you need the required grace, then double it.