You must be pretty young. Please remember that Taiwan offers you a pitiful pension. You may not think you need it now... the sooner you strat, the better.
Unless you have family here that takes you in for free, you have to pay for decent lodgings. I know what indecent abode costs, let alone what something healthy goes for now. If you have lived in the West, you may have certain needs, be used to certain conditions. Heck, I come from the 4th world, but there is a line I draw. That is why I pay my rent.
You need money for NHI -- which will be deducted as per your reported pay, not actual pay -- and also pay separate private insurance. Why? because if you live here with no family and fall ill/are run down by a blue truck, you are going to need it.
You will feel the need to escape the Island that has now become your shelter. Happens to all of us now and then. That is why we save money and take a brief trip abroad. It is cheaper than traveling in Taiwan.
You say you can live on 25k. Sure. I lived as a student on 15k... 20 years ago. Cost of living in Taiwan has been climbing steadily. It will keep on being more and more expensive.
Those are just examples on why it is better to have a 40k something salary than 25k. I think ICDF students get 25k... and they complain. Heck, see how locals live on 22k salaries. Now that is sad.
The thing is that it shouldn't be like that. Don't get desperate to stay or the bosses will use that against you. You want a visa at any cost, right? They will keep that carrot as far away from you just because they can. They have the power. The work visa is theirs, not yours.
That doesn't mean you should put yourself out like a mat. We Spanish speakers started a price war among ourselves because people wanted and needed income. Charging NT$ 300 or less an hour. Now, if Spanish speakers are a rarity, shouldn't Spanish lessons be more expensive? At least NT$ 600 per tutorial. But no. The price war meant losses for everyone. You start this, it may be contagious. And it is unnecessary.
As said, this will backfire and ruin your hopes for a longer stay. Do not stay at any cost. Sometimes, life solves itself if you relax. Others, it may be a way to tell you it is not meant to be. Or it can be a test of your resolve. But play fair. Follow the rules. From experience, if you break the rules to gain time, you will regret it a lot later.
You are getting