Cycle trip along the Han Gang

Where can I rent a decent cycle in Seoul? A hybrid or a dutch bike is what I need. I’ll be cycling for 5 days, would I just be better off to buy a cheap and chearful bike? Do you have any path suggestions? I lived in YoungsanGu , Seoul 10 years ago, and biked the Hangang a lot, but the paths have been expanded to include many tributaries. Any Suggestions would be helpful. Thanks