Hope this isn't too much of an 'opinion'. My observations have been that in a conventional stick built home the issue is getting a solid layer of insulation up on the outside of the studs and trusses. The places that stand out in the winter are where they are, as wood has a particular R value that you can't beat without there being some sort of 'break' layer. Which seems to be what is done with vinyl siding (likely not done for the advantage of insulation so much as it makes the siding hang and move better over the course of a year).
If it is a standard stick built house (and will work with your outside walls) I would consider a modest layer of sheet insulation as a thermal break layer (end of the day, what is the most effective for the money insulation). And plant wind breaks on the prevailing storm wind side of your home.
But that isn't what you asked -- you wanted to find a cheaper insulation source. Sorry, can't help, would like to see what you find.