<p>My Craftbot Plus Craftware slicer estimates cost per job based on filament prices I add as parameters.  What costs per meter would you use?  I created spreadsheets to calculate this for 1.75mm diameter filament and arrived at PLA = 6.6 cents per meter, ABS = 6.1 and PET XT = 18.6 cents per meter.</p>

<p>Edit:  thanks for feedback!  I paid \$22 per kilogram for PLA and ABS.  I paid \$57 for .75 kilogram of Colorfab XT Black.</p>

The simplest method is to divide spool price by its length. That's obvious I think. If PLA 1.75 (1kg net) has about 120m length and it costs 16usd then it looks like 1m costs arount 13c. =price/length
I think everyone can buy different filament at different price from different vendors so there is no good general price to enter into your slicer app. It has to be calculated each time you use new filament.
There are also other parts of the price. Electricity, time, wear, depreciation, know-how even the rent is some part of the ending price of the final product. Of course most of them are incalculable as they are permiles or so. But if you don't plan to sell it you can base on the filament price only.