You can make decorative table toppers pretty easily with very basic sewing skills. I like to use old mattress pads for the padding.
Simply cut the padding to the shape & size you want. A table runner can be whatever you like, either long enough to hang over the sides of the table or not. I’ve made some that are actually square. A table pad is like a tablecloth that does not hang over the sides. It usually covers the table top with about an inch of the table top showing. It gives protection to the table & adds color & often pattern.
Cut your decorative fabric for the top & the bottom a little larger than the padding. You can recycle old curtains for this either from your house or from resale shops. You could even use some Rit dye to give the fabric a shade that works better with the room’s color scheme. Or use fabric remnants you have or fabric you buy.
The backing fabric can be anything, including an old sheet. Pin the entire “sandwich” together, making sure everything fits. Trim any excess fabric. Use a long basting stitch on your machine to sew the 3 layers into one. Remove the pins as you go. Use wide folded bias tape in a coordinating color to cover the raw edge of your piece. Pin it opened once with the narrower side on the bottom of your piece. Sew the bottom of your piece so that your stitching line is just a bit inside the bias tape. Again take the pins out just before you stitch that section. Flip your piece over & fold the wider side of the bias tape onto the top of your piece. Stitch it down near the edge of the bias tape like you did on the under side. You’re done!
If you like quilted runners, etc. you could do some machine stitching on the sandwich of 3 layers after the basting stitch step. You should probably practice on some other fabrics first to see what works best for you.
A runner is really cheap to make with so little fabric needed. A table pad will cost more, of course, but with recycled fabrics it’s not bad. If you wanted to make a useful table pad that will be used under a table cloth, you could make it out of nearly anything. If you don’t have an old mattress pad to use for padding, you can use quilt batting from a fabric store.
Lots of places in the house can benefit from a runner: a kitchen island, the top of a fireplace mantel, a sofa table, and side tables. If you make them shorter they become placemats. From there it’s a short distance to making chair seat covers, hanging storage pockets, footstool reupholstering, fabric purses, eyeglass cases, & of course potholders. When you get good enough at this you can make gifts and/or sell some of the items. Have fun!
For some of the items you might find it easier to use a pattern from the fabric store. They often have coupons for these. You might ask at the fabric store how often they have the coupons.