Task 1 : I want to calculate the cost of this ad in text-only format.
Task 2 : I want to calculate the cost of this ad in "customized text plus some pictures" format. It means that I 'll use some different fonts and typographical variations and that I'll add some images somewhere inside.
How The Calculator Works Now
Step 1 : Select the Advertisement Category
Step 2 : Select the Publication
Step 3 : Click on Calendar to select Publication Date(s)
Step 4 :Select the Advertisement Type
Step 5 : Select the Advertisement Size
Step 6 : See Results
Solution for Task 1
Here we should use a text box. User copies and pastes her text/copy into the box, and our software counts characters, words, lines, width and height of the whole text/paragraph. Then, we gives estimate costs to user.
Solution for Task 2
Here, we should allow user to upload her ad copy as an image as in Facebook, Flickr etc. Then, our software will calculate its width, height and the estimate costs.
Basic image sizing, re-sizing are familiar to most programmers --- Imagick, Rmagick, PIL(Python Image Library), many PHP libraries and frameworks.
We know it takes many persons to change a light bulb at a company at Microsoft's level. You have many users so you must take extra special care not to break anything by your fix/enhancement.
I point this out just as an exercise and a reminder for future developments.
And I do notice that SPH has many other mechanisms and procedures to handle these problems very satisfactorily e.g. staffs at ads section can do this calculation for you. Maybe more cool alternatives that I may still be unaware of.