At mudfish, there are two plans you can choose; subscription and pay-per-traffic.

• Pay-per-traffic.
  I think you're already familiar with this plan and it was default from Mudfish v3. As you know, this plan charges mudfish credits based on how much datas (traffics) are used. At this moment, 90 KRW per 1G is general a price table (depending on the mudfish node, this could be vary). For examples, if you used 12 Gbytes using mudfish, this plan charges around 1 USD dollar.

• Subscription.
  This plan was introduced to prevent some cons of Pay-per-traffic plan at last year; for example, sometimes with misusing Full VPN mode, a lot of mudfish credits could be charged. With subscription plan, you can equip the game item you'd like to use at fixed price (at this moment 990 KRW per an item) for 1 month; no more extra charges. Full vpn mode is also possible but with speed-cap.