Popularization of mobile devices has turned mobile transactions into an irresistible trend. Banks have been actively developing mobile apps in competing for many business opportunities relate to them. In this study, a questionnaire survey was conducted for users of mobile devices in Taiwan by extending a TAM model that combines constructs of mobility and trust to gain an insight on willingness of users to use mobile apps to purchase financial products, as well as to better understand the relationship between the users’ purchase intention and other factors. 406 surveys were retrieved for this study; 215 were valid. The empirical results showed a positive correlation between the users’ views regarding mobile apps’ mobility and their perceived usefulness. There were positive correlations among perceived usefulness, perceived ease of use, trust, and purchase intention of financial product for mobile app users. Hopefully, the results of this study can offer a basis for reference by financial institutes in developing their apps and managing their relations with their clients.