So you think that inserting an invisible zip is hard???
Would you believe I use my STANDARD zipper foot. And it is NOT difficult to do it this way.
Most garments these days have an invisible zip. When the zip breaks, it may cost from $25+ to have it replaced by a professional. Or in some cases people throw the garment away. Seriously!!! Do it yourself. It's not hard with this eBook to help you.
There are 28 pages with step by step instructions. There are 12 videos covering each step and 13 illustrations.