You first need to determine which shank the presser foot uses on your machine. You can compare your shank (current presser foot) with these photos to see which one your machine uses.
NOTE: If you purchase a snap-on presser foot, you will also have to buy a "shank adapter" that will attach the presser foot to the needlebar. Here are some pictures of snap-on adapters:
Kenmore sewing machine snap on adapter Google Search
However, you will still need to make sure to buy the correct adapter for your machine. The GREAT thing about buying a snap-on adapter is you can add a lot of presser feet to your sewing machine accessories because you can purchase additional snap-on presser feet or even a complete set of snap-on feet that will all work with your adapter and your machine!!!
Kenmore Presser Feet eBay
You will just snap one foot off and snap another on!!! Great idea!!!
OR--you can take your current presser foot along with the make & model of your machine and check with the local sewing repair shops to see if they have what you need.
FYI, once you know what shank your machine has, you can probably also find other specialty feet for your machine, ie walking foot, free-motion foot, etc.