Niantic should charge for all medals
The financial viability of Ingress (and especially of anomalies!) for the future is important to us all. Charging for anomaly medals does not, in my view, go far enough.
As soon as possible, Niantic should enact a charge to receive ALL in-game medals: $5 per tier, per badge, all previous tiers required to unlock the next one.
If you've caused 200,000 reso deploys worth of server usage, you can stump up the $25 for the onyx medal in order to show the world your achievement. Seems reasonable, no?
Perhaps Explorer, Pioneer and Mission Day could have a higher fee with some of the additional revenue invested in carbon offsetting, to mitigate the travel required to earn these badges at the highest tier.