Olive oil and butter may seem expensive but you only need small amounts to add both fat and flavour.
Homemade flavoured butter works well.
Put a block of soft butter in a processor, add mjnced garlic, herbs, spices, lemon to taste and whizz it all up. (Or beat it in a bowl by hand). Then divide into small portions and freeze, an ice cube tray works well for this.
You could divide the butter an do 2 flavours at once
Then you have instant fat and flavour whenever you need to to jazz up sausages, mince or eggs