Agreed that you can just wear a sweater and a "normal" belt and that belt will be covered up...

But I've come to the conclusion (after having gone sporran-less in the beginning of my kilted kareer) that the sporran is de rigeur. If nothing else, consider a Stillwater Nylon Nightstalker sporran as a reasonably priced and extremely practical possibility. Not only is the sporran traditional and what folks expect to see hanging on the front of the kilt, it is also damn near indispensible if you want to carry anything (like your wallet and keys) with you and just feels right sitting there on the kilt.

Best

AA