How to do costing for a product? Asuming it is a consumable item.Variable cost? Mark up % from unit price?

Answer 1

Do you mean "costing" or "pricing?" If you want to know how to price something, do a market analysis to see what competitive or similar products are sellling for. It's doesn't matter how much it costs you. The only thing that matters is what the market will bear. If you can't make a profit at this price, then cut your costs or get out of that market.

Answer 2

You buy an item for a COST then mark it UP to the price you sell it for.

Consumables could be beans and rice or could be Bollinger Champagne. Beans and rice are %mark up, slim profits. Champagne is fat profit and whatever the market will bear.