It's this.

Unfortunately I have a Husqvarna Viking sewing machine and all the accessories cost a small fortune...I don't think the ones from Nancy's Notions would fit.

This is going to sound odd, but I remember reading or hearing somewhere that you could do free motion with no foot at all. I just tried it, and it does work.

That's risky - those needles are sharp and it is so tempting to reach into the path of it - particularly when there is the distraction of children. Not something I would risk.

OOOOOOH...that's not a good idea...I'd go further than "risky"...that's Dangerous! Safety first, Safety second, Safety, third...etc. Please don't try this. Perhaps someone you know would loan you a darning foot to try before you purchase one of your own.

Try without a foot by placing the area to be quilted in an embroidery hoop and do not reach inside the hoop area while needle is moving.

I freemotion without a foot all the time. I use a large embroidery hoop sometimes and sometimes I use a iron on backing or nothing depending on the pattern I am doing.

You do need to drop the feed dogs and use a new sharp needle. Bring up the bottom thread and take a few stitches in place and cut the threads off and then off you go.

Use some common sense and don't get your hands any where near the needle. This is just as a caution ... I know you aren't simple minded. I just had to say that so anyone trying this would take care. Hands go at three and nine o'clock. I use the cotton gardening gloves sometimes that have the little dots of rubber on the palm of them.