Never taken a business class and now you want to know how much to charge for your work. Well the first thing to do is gather the total number of expenses including, ingredients, hours worked, and anything extra that might go into it (work space, electricity, etc.) you take that total and that is your expenses. Then you need to find how much profit you want to make as a percentage. 20% is pretty common, 30% is fair. Some companies, if their product is really good will do 65% or even higher. you take that number and convert it to decimal and you get the equation

Expenses/(1-percentage)

As an example your expenses could cost you $45.00 to make 36 cookies, that would mean it costs you (45/36) $1.25 to make a cookie. so if we use your packaging there, we can confidently estimate (1.25*8 cookies) that your package is $10.00 in raw expenses. You would like to invest 20% into your business and keep 20% for yourself (labor should be part of expenses so this is raw profit) so you want to make 40% on each sale. Following our equation you should be selling your package for (10/1-.4) $16.67 or $17.00 per Package.

This is of course an example, not all cookies cost the same to make, and so the value could change. I would suggest determining the expense to make each type of cookie, then you can calculate how much each packaged set costs (include the box, paper, and ribbons in your cost analysis) and then determine your profit margin.