by free:

通过免费的

Today， this initiative has been superceded largely by free WiFi access because people buy more and more laptops.

如今，这一举措在很大程度上已被免费 WiFi 访问取代，因为人们购买越来越多的笔记本电脑。

for free:

免费

Are the meals for free?

这些饭是免费的吗