The making and use of ink has been part of human history for at least two thousand years. It's certainly been a basic element of magic for a very long time. I like to make my own ink for use in spells that require writing. It's very easy to do so, and it adds a personal touch that, I feel, increases the momentum and power invested in each written request.
You can buy a quill for use with your homemade ink at most craft stores, but I have better luck with a fountain pen. You will probably also want to purchase some quality paper if you're going to go to all this trouble, but the results are well worth the extra effort.
Here are a couple of ink recipes to help get you started:
Walnut shell ink
12 walnut shells, hammered into small pieces
1 cup distilled water
1 tsp vinegar
A glass or ceramic saucepan
Put the water and the shells in the pan and bring them to a boil. Reduce heat and let them simmer for a half hour to 45 minutes. Remove them from the heat and allow the mixture to sit for at least 8 hours. Add the vinegar, strain out the shells, pour the finished ink into a small bottle and store it in the fridge until you need it. Don't forget to shake it before use. This makes a pretty, dark brown ink.
1/2 cup of blackberries (you can also use blueberries)
1/2 tsp salt
1/2 tsp vinegar
Mash the berries and force them through a fine mesh strainer to juice them. Add the vinegar and salt and the ink is ready to use. It doesn't keep well, but it makes a very pretty ink.