I have refilled my pods for years. I purchase my refill supplies from my-cap.com They have the disposable pods, filters, and caps. I reuse the pods several times before I replace it with a new one. (they usually come 100 in a pack)
The caps are made of hard plastic and will last for years. Check out the videos on you tube. I like the idea of adding pumpkin pie spice and cinnamon to the coffee - I never thought of that.
Yesterday at HyVee I purchased a box of Gevalia Caramel Macchiato K-Cups and it is delicious! It even makes the frothy top. I also purchased a French Vanilla Cappuccino and was pleased with that one too.