Work out what a resin print costs from the slicer's ml estimate, your bottle price, and a waste allowance for supports, failures and the vat.
Cost = print millilitres × (1 + waste) ÷ bottle size × bottle price. The slicer volume already includes supports if you sliced with them; the waste allowance covers failed prints, resin left in the vat and wash losses. IPA, gloves and filters are extra.
Take the millilitres your slicer reports, add a waste allowance, and multiply by the bottle price divided by the bottle size. A 45 ml print with 10% waste from a 35-per-litre bottle costs about 1.73.
5-15% is typical. It covers the occasional failed print, resin that stays in the vat and on supports, and losses during washing. Raise it if you print tall thin models that fail more often.
Yes, if you slice with supports enabled the reported volume includes them. Slice the final supported model before reading off the ml figure.