Not very, around $1000 or get a second hand one from the office clearence store (say North point, Sham shui po ). Compare the level of safety to the liposac. When you have a "fat" lipo back and you don't wanna to throw it away immediately,and you wanna to sleep well, it is wortwhile.
Some friends store their lipo packs in their bath tubs when their families are going aboard for long summer holidays.