I’d say make a sweet cream (50% heavy whipping cream, 35% 2% milk, 15% vanilla syrup / vanilla extract) then get some pumpkin purée (just a tablespoon) and a crap ton of pumpkin spice seasoning

The foam is vanilla sweet cream plus 2 pumps of pumpkin spice.
Vanilla sweet cream is made in house it is 2% milk, heavy cream and vanilla syrup

The foam is created by a special vitamix blender blade:
$1


We can make the foam with any milk or dairy alternative, but the consistency changes from liquid to liquid and also depends on factors like additions and the type of foam we're trying to make.
As a Barista, My best advice for a quick-and-dirty budget substitution would be to find a Pumpkin syrup that you like and use that in conjunction with some vanilla creamer. Make Iced Coffee or Cold Brew at home; you can make this by the quart or gallon easily and it will keep 3-5 days in the fridge.

The foam is arguably nothing more than a pretty accent (I know, It tastes good!) but there's a reason the Cold Foam costs an extra dollar: that lovely, velvety gold takes some work to get there.