If you don't have a sewing machine, then hemming tape is an option, HOWEVER, I do not believe it is a good option.  The problem with hemming tape, is that if the person changes their mind and wants the garment hemmed properly after the hemming tape has been ironed on, the sticky on the tape will ruin your needles.

Added to this is the fact that the hemming tape will not stay up forever.  It can also ruin the fabric.  I have seen people use this tape on silk, and it looks dreadful.

So if you don't have a sewing machine, consider using a clothing alterationist rather than using hemming tape.

Happy sewing

Judith aka genie