Can I play the bad guy?
I wonder if the current suggested bands are too low. There's not much of a gap in price between being a just-about-qualifying silver member, and being a crystal member. Perhaps they could be widened slightly - so Crystal reflect tier 5, rather than tier 4/5. I understand that the majority of our members are younger, but 10$ is probably a basic transaction fee, so for it to jump straight to the Gold tier seems odd.
Assuming it'll work like it does now, you've also got to think of other countries and conversions. I know, from a UK perspective, $5 is around £3 - which is about the price of a cup of coffee. Most kids get a lot more than that for weekly pocket money :<.
I reckon a bump of $5 would be a better alternative.
Silver Tier - $5.00 - $14.99 (Tier 1/2)
Gold Tier - $15.00 - $24.99 (Tier 3-4)
Crystal Tier - $25.00 + (Tier 5)
I like the idea of the perks though, definitely makes the levels more distinct with clear incentives to donate.