Priced at just $11 (£8), the pouch was designed by a Singaporean student at Pathlight, the country's first autism-focused school.
PM Lee Hsien Loong and Ms Ho have been in Washington since Monday.
Initially, Ms Ho's choice of accessories was met with some criticism online.
But, once it was discovered to have been designed by 19-year-old Seetoh Sheng Jie of Pathlight, sales of the pouch jumped.
The school typically sells 200 pouches in four months, but sold 200 within a day after images of Ms Ho were shared widely, the school told the BBC.