I can see how you could potentially do this using a combination of regex in the classification rule builder and a calculated metric. It's pushing the limits of what is achievable but it might just be do-able...
For the sake of explaining the concept let's simplify things by make the (false) assumption that your products range in value from $1 to $999 and are in whole numbers (you'll need to expand the concept to cover other values!).
First Stage: classifications
create 3 classifications, one for the units, one for the tens, and one for the hundreds.
Then use regex in the rule builder to dynamically split the value into the 3 classifications. Your regex is going to look something like this:
For the units (^\d*)(\d$) returning $2
For the tens (^\d*)(\d)(\d$) returning $2
For the hundreds (^\d*)(\d)(\d)(\d$) returning $2
For example if the value was 874 then:
"units" classification would be dynamically set to "4"
"tens" classification would be dynamically set to "7"
"hundreds" classification would be dynamically set to "8"
Second Stage: calculated metric
You've now got to build a calculated metrics along the lines of:
If "unit" equals "1" static number 1
Plus
If "unit" equals "2" then static number 2
Plus
If "unit" equals "3" then static number 3
.
.
.
Etc. (all the way to 9)
Plus
If "tens" equals "1" then static number 10
Plus
If "tens" equals "2" then static number 20
Plus
If "tens" equals "3" then static number 30
.
.
.
Etc. (all the way to 90)
Plus
If "hundreds" equals "1" then static number 100
Plus
If "hundreds" equals "2" then static number 200
Plus
If "hundreds" equals "3" then static number 300
.
.
.
Etc. (all the way to 900)
Obviously in the real world you'll need to expand the concept for more digits.
It's pretty crazy but I think it would work. Let me know if you try it!