When looking for Tainan Hotels, there are many options. The Tainan First Hotel is probably the cheapest I've stayed in during my trip in Taiwan so far. Here's my full review.
Traveling to Kenting (墾丁)? Here's a full review of Kenting 157 Boutique Hotel, located right on Kenting Street. The location is perfect if you want convenience during your stay in Kenting.