I had some of those coffee bags once, the card hangers kept slipping and breaking, so the open bag of grounds fell into my mug. Wasn't impressed with them at all
Waitrose has coffee pads that are basically oversized teabags. You just put them in a cup and treat as you would a tea bag
only down side is that when I last looked it was only a fairly low strength (2 or 3) flavour. Each pad was individually wrapped fo freshness and I have a few in my car for going away with if I forget my cafetiere
Another option that I have tried are the filter cups that sit on top of your mug and you pour through, just like the OP, but are rigid plastic. They weigh nothing but take up far too much space