Your first outpost will cost you only 187,500 per resource only and will increase by
187,500 per resource every time you capture an outpost. So basically if your gonna capture your 4th outpost then you can just simply multiply
187,500 x 4 to get your take-over cost which is only 750,000 per resource.
So, Is there a cap like last time?The answer is yes, But Unlike as anticipated it's not capped at 30m per resource but still capped at 20m per resource. I did the math and you basically get capped when you get to your 107th Outpost. So if you have more than 106 Outposts then you'll take-over cost will not increase anymore and will stay at 20m per resource.
Note: This Outpost take-over cost is only temporary and Next week Dave(Creator of Backyard Monsters) is gonna change the take-over cost again continuing his plan of a gradual increase in take-over cost in 4 weeks. Here's the post regarding this matter.