An electronic bus pass - finally

I live in the town on Yeonggwang but I teach at two elementary schools in Baeksu so I take the bus. The ride takes 20-25 minutes depending on the school. There are a few quirks that I am still getting used to with regards to the local buses. For example, on my way to school in the morning I pay 1,300 Won when I get off the bus but in the evening I pay only 1,200 Won (for the same ride) and I pay as I get on the bus.

The drivers can make change but it is a bit of hassle to use cash. Today, with the help of a Korean friend, I was able to purchase an electronic debit card. The 'card' is really a small keychain accessory (see the purple object in the photo below). I bought it from the vendor inside the local bus terminal. The card cost 5,000 Won and I added 25,000 Won of credit to the card. I am told that it will work on the buses, subways, and taxis in Seoul. Unfortunately it is not on the same system that Gwangju uses.

UPDATE (MAY 12th): The bus pass only worked for me twice. I tried to return it but the vendor gave me a phone number to call. Of my initial 25,000 Won I was only able to use 2,300 Won. The remaining 22,700 and the 5,000 I paid for the device are a loss. Rather than risking more money, I'll just continue to use cash.