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 since Mudfish v3. As you know, this plan charges mudfish credits based on how much datas (traffics) are used. At this moment, 135 KRW (South Korean Won) per 1 Gbytes is general a price table. For examples, if you used 8 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.