a little bit, sometimes
些 centers on a small, indefinite amount or degree: a little bit of something, or an occasional, sometimes occurrence.
些 combines 此 (this) and 二 (two), likely suggesting a small, indefinite quantity—'this and two' as a modest amount. The exact historical development is uncertain.
此 (this) plus 二 (two) gives 'this and two'—just a little bit, not much. Sometimes that's all you need.
For サ, imagine a small saucer with just a little bit of tea: saucer -> サ, and the saucer holds only a small amount.