1. I'd better get going.

(What is the meaning of 'get going'? What other expressions can we use?)

That phrase just means "leave and go on my way" or "leave and get my errands done" or something similar. It's very idiomatic!

I'd better leave and go on my way.
I'd better leave and get my errands done.
I'd better leave.

The expression "get going" is commonly used to mean that someone is leaving or starting to go somewhere. It implies that the person wants or needs to start their journey or activity without delay.

There are other similar expressions that can be used interchangeably with "get going" to convey the same meaning. Here are a few examples:

1. "Get moving" - This has a similar connotation of starting to take action or leaving a place.
2. "Get a move on" - This expression is often used to urge someone to hurry up and start their journey or activity.
3. "Hit the road" - This phrase specifically refers to starting a journey by road, but it can be used more generally as well.
4. "Be on your way" - This expression emphasizes the act of leaving or starting a journey.

Remember, when using any of these expressions, it's important to consider the context and choose the one that best suits the situation.