Pin value 'band'?
I tend to think in categories.
GWP/PWP/Hidden Mickeys/the pins you get for booking travel packages - the lowest category, and if I had to put a price it would be $4 or less.
Open edition/high LE pins - These are the pins that people end up selling in the $5-$10 range. I sort of try to match up original price, and figure that most of these have "depreciated" equally. The wants vs trades tend to be pretty equal, or more traders than people wanting.
Low edition pins - WDI, soda fountain, Disney shopping, etc. I kind of figure these start at original price and some have appreciated a bit, while some have depreciated a bit. Wants vs trades can sort of sort that out, and I pay attention to posts about which ones have ended up in the discount bin or sold cheaply at the semi-annual pin sale
Very HTF/ Extremely Low LE - $$$ You can usually identify these pins because there will be a great disparity between number of people trading vs number of people wanting. I tend to try and use Ebay to sort out values.
The last category are the ones that people tend to be more sensitive to disparities in value. And somewhat the 2nd to last, but then it kind of depends on accessibility. It seems like people with easy access to low LE stuff, seem to be satisfied if the pins in question are more or less the same retail price. People who had to set up a purchase, or got it on their once a year trip are more sensitive.