Need input: Temporary purple hair dye

The girl wants to col­or her hair pur­ple but has wise­ly decid­ed to try a tem­po­rary col­or before going with the per­ma­nent stuff.

Her nat­ur­al col­or is hon­ey brown/dark blonde. She does NOT want to bleach her hair first.

Any rec­om­men­da­tions as to brands of col­or to try or avoid? Oth­er advice from those who have explored such things themselves?