The best way to add product options and pricing is by adding "Variations" on the final step of the add/edit product tool. Here's how:
1. Click to edit the product, then click “Next Section” at the bottom of each page until you get to the 4th, final page
2. Select how many variations you'd like
3. Select the type of variation (ex: color, size, etc)
4. Enter the name of a variation, then separate by comma or hit Enter to add another (ex: red, blue, green)
5. The variations will appear below. There, click the + sign to edit their prices, stock counts, etc.
6. When done, click "Edit Product"
If you'd like to see the process in action, click here for a video on editing products.