I was tiring to build an app which uses google maps for showing places and Pace API for searching places. but it is not being possible to build the app with two different AP
Yes! you can use same key on both of and also you can use only one key for all Google API
See below image in listed all google api and see this link.
Now you have to Enable all of api, Here must enable API you have require in your app. see this
Now get Stared with this Link