What are the mix and match categories? What items are included in the mix and match categories?
Currently there are 2 mix and match categories: Pen Kits and Acrylic Pen Blanks.
Pen Kits Mix and Match Category: All pen kits are a part of the pen kits category. The discount level for each individual pen kit is determined by the total number of ALL pen kits in the shopping cart. Bushings, tubes, drill bits, etc are not included.
Acrylic Pen Blanks Mix and Match Category: All acrylic pen blanks are a part of the acrylic pen blanks category. The discount level for each individual acrylic pen blank is determined by the total number of ALL acrylic pen blanks in the shopping cart. Natural wood blanks are not included.

Other items (boxes, drill bits, bushings, etc) are not in any mix and match category.

If an item does not display the mix and match image it is not a part of any mix and match category.

How do I know my current discount level?
The best way to know where you stand for discounts, is to go to the individual product information page for any product you are interested in. There you will notice (if applicable) what the price breaks are, how many qualifying items you have in your cart, and how many items you need to add to get to the next discount level. An image from the product information page is shown below with important details highlighted.

1. The mix and match image appears anytime an item is in 1 of the 2 mix and match categories. The accompanying text indicates which category this item is in. In this case, the Lava Flows pen blank is in the Acrylic Pen Blanks mix and match category.

2. This row appears whenever you have qualifying items in your cart. It shows how many qualifying items are in the cart, and how many more you need to add to get to the next discount level. Qualifying items are any items that are in the same discount category as the item you are looking at. In this case, since you are looking at an acrylic pen blank, the qualifying items are acrylic pen blanks and you have 21 of them in your cart and if you order 9 more acrylic pen blanks you will receive the next price discount level. The 3 lava flows pen blanks have not been added to the cart yet. The discount level only changes after an item is added to the cart.

3. This indicator shows which discount level you are at, it only appears when you have qualifying items in your cart. In this case, you are at the 20+ discount level, and if you add 9 more (see #2) items, you will be at the 30+ discount level.

4. This shows the contents of your shopping cart. In this case, you can see that there are 21 acrylic pen blanks, and even though you do not have any lava flows blanks in the cart, you are already at the 20+ discount level because of the other qualifying items. The 15 pen kits in the cart do not impact the price of the acrylic pen blanks. They would impact the price of pen kits.