I solo traveled on a budget. I originally brought $220 USD in cash to pay for food, transportation, and incidentals. I didn't expect medicine to be close to $100. Otherwise, the $220 would have been a comfortable amount for my trip. Although I could have technically budgeted everything using only $220 (which almost half of it was for prescription medicine), 3 days before leaving, I ended up deciding to splurge on desserts and took out an additional $50 from the ATM. My reasoning was that the desserts in Korea are half the cost in the US and I rarely buy such desserts in the US due to their cost.
If I could do this over again, (1) I'd bring $300 USD cash. (2) I would also immediately get a T-Money card before traveling out of the airport. (3) I would use the bus system for traveling to/from the hostel/clinic.
Hostel- $335 USD total cost for a 12 night stay. I booked through Agoda. There was a flash sale so that's why my stay was cheap. I chose to stay at Myeongdong in a single occupancy room. It's a very tiny room. The only con about the room was that the sink drained slowly.
Taxis- I did not use any taxis. However, after surgery, the doctor called (and paid) for my taxi ride.
Transportation to/from airport and hostel- 8500 won roundtrip. I used the Airport Railroad Express (AREX) train to travel from the airport to the hostel (and vice versa). There are 2 versions: non-stop and all stops. Both take ~1 hour to reach Seoul. I used the all stop train and it costs ~4250 won per trip. The non-stop train is ~9500 won per trip.
Transportation- ~40-50k won; at the beginning, I took the subway a lot and transferred 2-3 times (2400-4800 won) for a one-way trip. Originally, I thought transferring to the next station was free, but when I realized that was not the case, I began using the bus to get to my destination without needing to transfer, and that cut back on my transportation costs.
Using a T-money card, you get a 100 won discount on bus and subway rides. Discounted subway rides cost 1250 won. Discounted Bus trips cost 1200 won. Bus transfers are free if used within 30 minutes of scanning your card before exiting the bus.
I highly recommend using Naver map app to show real time bus schedules, trip cost, and directions from your current location to the bus stop or subway station.
Food/water- ~150k won. Water was free at my hostel. Due to my dietary restriction, I ate at a small local restaurant almost daily and occasionally at the night market. 3000 kimbap, 7000 bibimbap, 8000 kimchi fried rice, 5000 fruit cup, 6000 nutella crepe, etc. I also packed granola bars and protein bars from home and had those as snacks.
Translator- did not need because all the clinics I consulted with had English translators and all the doctors spoke some English.
Medicine- 93k for antibiotic medicine, antibiotic ointment, and eye drops. The eye drops cost ~50k for a box. Next time, I would not buy the eye drops at that price. Before I left, the clinic recommended that I buy an additional emergency supply of antibiotic medicine (in case an infection happened while I'm at home). As it was optional, I passed on that. The clinic sold scar ointment for 43k won. I bought scar cream at home for $21 USD.
Portable wifi device rental- $33 USD. Before my trip, I reserved a rental for a portable wifi router. Pick up/drop off location was at the airport. With this device, I could use the Internet while on the go. For security reasons, I used this wifi internet instead of the hostel's internet. It was very convenient to have.