I am looking for a free API similar to google translate that can work with my python bot. Is there any similar API available or is there a way to use the google API for free?
First of all, you shouldn't have to worry about the fact that you are using Python. You can use libraries like Requests to make calls to any accessible REST service with an API.
Lots of services will be free based on usage. They do tier pricing so that with enough usage, the service starts charging. Google offers most of their services beginning on a free tier. For example, Google Translate's service is free for 500,000-1,000,000 characters. You will run into similar setups with different translation services.
Here are some of the most popular/robust options. You can look for "Pricing" or "Usage Limits" to get a better sense of how much you can do for free.
Yandex Translation Tier Pricing (UPDATED June 1, 2020)
Microsoft Azure Translation Free to begin
IBM Watson Translation Free to begin
SYSTRAN.io Translate Free
MyMemory Free with usage limits