There are no capital requirements.
If you are here in Taiwan already, you can either set up the company yourself with the information in Elias Ek's useful book plus the information on the Invest in Taiwan site.
Alternatively, get help from an English-speaking accountant such as JusRegal. It's much cheaper than going to a lawyer and they do a good job.
Lawyers are more useful if you are outside Taiwan and the investor is a corporation. I wouldn't recommend randomly hiring a Taiwanese lawyer. Most are not business lawyers. Another situation in which a lawyer is a good idea is if you have a group of investors. In that case, you probably need advice on shareholder agreements and structuring things properly. If you are a US citizen, it would be a good idea to consult a US lawyer or CPA about US tax issues.
Good luck--and make sure you understand Taiwanese law on return and refunds if you are doing an online business.