Wait for Pixel 4 Deals
Ther are already some good Pixel 4 deals that will help you save, but most of these are store credit or buy one get one. If you go for the Buy One Get One deals, you will need to qualify for thes offers and most of the time this means adding at least one new line.
If you are willing to wait until Black Friday, you may see some bigger Pixel 4 deals without the need to add a new line, switch carriers or buy two devices.
Best Buy had the Pixel 3 for $400 off on Black Friday on Verizon and it's possible that we could see a repeat of this promotion on Verizon or on another carrier next month.