Membership pricing: sliding scale from $5/mo (suggested $15) across docs

terms-of-service.md

@@ -24,7 +24,8 @@ When you join, you become a **member** — someone with a voice in how the proje
 
 ## 2. Membership
 
-- Membership is through **Open Collective**, where you pay dues on a sliding scale.
+- Membership is through **Open Collective**, where you pay dues on a sliding
+  scale (currently $5/month minimum).
 - You must be **18 or older** to join.
 - Membership is governed by our [Charter](charter.md), including our Code of Conduct.
 - We may suspend or remove membership for Code of Conduct violations or non-payment, as described in the Charter.