A zipper foot is narrower, allowing you to get closer to the zipper. I have sewn in zips just using a regular foot (I sew on vintage machines). It is do-able, but I did end up buying a generic zipper foot that fits my vintage machine. There is an Aussie girl on e-bay who has feet made up for vintage machines (they probably come from China) - Don't think she sells to overseas buyers, but in the USA you have more chance of finding an original for yours. So go ahead, but just keep it slow and steady as on small purses it's a bit fiddly.