In simple words cost can be defined as those the total money, time and resources associated with a purchase or activity.

To ascertain those costs following techniques are used:

Historical costing : In this technique actual costs are ascertained after they have incurred hence in this method there is no scope for control of costs.
Absorption costing: [...]

Well the basic difference between job costing and process costing is that in job costing work is undertaken as an individual unit and manufactured according to customer’s specific requirement while in process costing is suitable for industries producing homogeneous products and where production is continuous.

Here are some more differences between job and process costing :-
Job [...]

Job costing can be defined as a kind of precise order costing where work is undertaken as an individual unit and manufactured according to customer’s specific requirement. It is perfect when the products to be produced are dissimilar and non- repetitive in nature like that in case of ship building, printing, advertising etc…