I need to have a teflon foot to sew on vinyl for a "by Annie" bag I'm making, but my machine doesn't have one. Does anyone know if you can put something on your regular foot to make it slide over vinyl easily?

I used a piece of tissue paper between the vinyl and foot. It will tear off easily. Use the kind used in wrapping gifts not Kleenex

A walking foot works pretty good for vinyl, too.

Depends on which machine you have. There's a fair amount of interchangability between feet on modern low shank machines. What do you have?

I use just sheet of copy paper under the vinyl only cause it sticks to my machine bed. I don't find much sticking to the machine foot, but if that happens I use tissue paper and tear it off later.

I use tissue paper too. Scraps will do. I would be hesitant to put anything on my regular foot....might be difficult to remove and if left on, may mess up how the foot works on fabric. Also if you end up sewing with the vinyl down, just put a piece of tissue paper on first, makes it slide much easier on the bed of your machine.
What By Annie bag are you making? I love her patterns and the last ones I made was the "Open Wide" zippered pouches. They are great.

I bought a teflon foot from Amazon and it was maybe $6.00, I tried the scotch tape under my regular presser foot that didn't work for me. I also saw a video on YouTube that gives you 3 recommendations for sewing on vinyl. Third one was to put a very small amount of talcum powder on the bed of the machine, she demonstrates this and seems to work for her. The only thing I personally have tried was the tape and as I said it didn't work for me. I got my teflon foot in 2 days so I would rather have waited than to have shredded tissue paper allover my studio.

Parchment paper.

I don't thing I ever used a Teflon foot on my by annie bag, just a walking foot and zipper foot. You can use tissue paper but I didn't feel the need to

I am making "Everything In Its Place" bag. I'm about halfway through--getting ready to sew zippers on vinyl pouches. I taped some tissue paper on the bed of my machine and some scotch tape on the bottom of my foot. That seemed to work.