I have to agree with thanee, if you have 8 slots anyway then getting a couple of extra different ones is effectively a non-issue, chances are very good you wont need 12 different spells of the same level in one day, and chances are very good you will want duplicates of a couple that are there.
I simply cut the cost of the current rings in half and made them only for people who prepare spells. I made another type of ring for spontaneous casters, and made up something similar to pearls of power for them.
As for the items above, it is really hard to say. But something like the prices you have up there are probably close to ok. The first is obviously fine
keep the 10, 30, 60, 120k and roll with it. 120 is not chump change for anyone, and by the time it is really able to be afforded even 4th level spells dont matter as much.
I simply cut the cost of the current rings in half and made them only for people who prepare spells. I made another type of ring for spontaneous casters, and made up something similar to pearls of power for them.
As for the items above, it is really hard to say. But something like the prices you have up there are probably close to ok. The first is obviously fine

keep the 10, 30, 60, 120k and roll with it. 120 is not chump change for anyone, and by the time it is really able to be afforded even 4th level spells dont matter as much.