@MKSandra Welcome to the community. I think the easiest way to do this is with variations.
1. Go to your item library and select Create Item, upper right hand corner.
2. Fill out all your information as normal for the item.
4. Scroll down and click on Variation and, then click Add Variation.
5. The Variation page will open, from there you can put in your sizes and assign each size their owe price. See photo below.
The first photos shows how you can have the size and add Tall to it, the send photo allows you to save the sizes for future use. the third is how it will look on the items dashboard.
If you look at the photo below you can select custom attributes and there you can pull all your colors in. For instance you have Blue, Red, Green,Yellow, Orange. But on this item you only have the shirts in 3 color Blue, Red and Yellow. In the attributes you can just select those 3 colors. When you save the item and when a customer goes to your website to order, they will see Color with a drop down menu to select the color they want, then select the size. So if they want a Blue 2XL Tall it will show the price of 25.99, If they want a Red Large it will show the price of 19.99. The good thing about doing it like this , is on the receipt it will say 2XL Tall so the customer will know why they were charge 25.99 instead of 19.99.
If you run into any problems just reply back and we will help you out more.
