Splenda - or other Sucralose sweetener

I’m looking for Splenda, or another Sucralose sweetener in the Taipei area.

I’ve heard that it’s found at Costco. Is it found anywhere else?

Note: I cannot use anything with Aspartame.

Edit: found it at Costco - worth the signup fee.

I’m sure I saw it in the basement supermarket (City Super?) of ShiLin Sogo. But that was a while ago.