the DiDi app lets foreigners register using a foreign credit card and phone number. However for your first trip it requires that you prepay, and will not let you use a foreign credit card for pre-payment, so you get stuck.
What Is the Difference Between DiDi Chuxing and Uber? Both company's offer ride-hailing services. DiDi actually bought Uber's China operations in 2016, so Uber no longer operates in China. At the same time, DiDi does not operate in the U.S.
Cooke suggests all ride hailing apps tend to be cheaper than taxis, although large surges can change that. “Without surge, [ride sharing] is 30-40% cheaper than a taxi.”