Push Notifications limit?

I’m just wondering how many Push Notifications I’m allotted on the free plan before having to upgrade?

I found the answer here: https://backendless.com/pricing/backendless-cloud-functional-limits/

Is that 1,000,000 messages is per month for free plan? Or we must upgrade after 1,000,000 messages?

What’s that 1,000,000 means?
Let say I have user base of 1000 users; then ever msg I push will reach 1000 users.

Is that case like I can push max of 1000 messages?

Kindly clarify.