I've put costs in three places: average price of high speed rail ticket, price of bike hire for a day and price of return bus ticket. Other costs such as accommodation vary so much depending on solo or in couple or group and type of place, hotel, homestay etc. So I've left that out. Costs of getting to Taiwan also differ based on where you're coming from, I was travelling for 18 months and came from Hong Kong. The costs I have given provide a rough idea for budgeting and I've mentioned that Taiwan is affordable.