This may have been covered at some point in this long thread, and possibly we're well past the point of this being remotely useful to consider, but some input taken from game design:
Point Buy Systems.
Rather than trying to fix a budget based on potentially changing prices from year to year, consider building a class to a set value of 'points'.
You get X points or credits to spend, and then common off the shelf materials get assigned point costs.
Standard base unit sheet of plywood: 10 points (+ points for thicker, - for thinner)
Roll of Tyvek: 5 points
Standardized container of resin: 10 points
etc.
Overall balance is then controlled by the total number of points allowed, and then the values set for any given unit of stock material. This keeps a given design valid from year to year in the face of material price going up or down, simplifies the 'book keeping' for people to stay within the 'budget' ruleset, and maintains the challenge and flexibility of 'what can I build with this?'
A point buy would also greatly simplify regional variance - I have no idea of what current prices are, but I assume the boat I could build in Victoria BC is probably different than what I could do down in Seattle, and removes the question of "Well what exchange rate would we use?" when comparing the two.