You can use a colorlight card to control the panels, they can be had for $15 and connect to the nerwork using gigabit ethernet ( must be gigabit ). You then send then data using the windows software or you can use a Pi/computer running FPP software to send whatever you want.

This would reduce cost to:

2x panels

1x colorlight card

1x power supply

Misc cables / case

Edit: The card can handle an 8x8 matrix of panels ( IIRC ) and the cards can be chained together to make larger displays. I dont recall the max size. The biggest I’ve made is 5x5 for a xmas display.