I thought about getting a pod machine with reusable cups and refilling them, but I ended up getting an inexpensive espresso machine and coffee grinder instead. I’ve had it about 5 years now. I figured refilling the portafilter would be as easy (or easier) than refilling the reusable cups.
Some sort of single-cup drip machine would be intriguing, but I couldn’t find any that looked good to me at the time.