I'm going to stick with the 'rules' of your request.
One item over $20: an acrylic extension table for your sewing machine (Sew Steady is a good brand) or a drop in cabinet if you can afford one
One item under $20: a small pair of sharp scissors (they do not have to be expensive, but they do have to be easy to pick up and slip on quickly for trimming threads and fabric corners while at your machine)