I have this same problem. I was thinking of buying seat covers. Its a jeep wrangler btw.

Don't they sell a vinyl repair kit that you apply and either use heat or if catalyzes up and sort of fixes the tear?

I did exactly as you already suggested to the front seats in my old beetle. I used duct tape to basically re-cover the entire seat. I laid down strips in both directions, and pulled it tight to compress the padding a little, wrapping the tape clear under the bottom of the seat frame. Then I used a seat cover to cover the tape. It worked pretty well for a couple of years. The tape goo eventually dried out, and began to peel back from the underside of the seat frame, but the tape still held OK over the original vinyl upholstery (this was in Las Vegas, stored outside in 115 deg. summer heat).

Of course this was for a ratty VW, which was otherwise smitten with character such as red-oxide primer, missing sunroof, a petrified snake skin in the back, etc..

lydia, what kind of fabric is on the seat? is it vinyl or is it a woven fabric?

if it's vinyl, you could investigate the vinyl patch that Clif mentioned, and if it's a really big rip you could try using a heavy-duty adhesive to glue a strip of vinyl at least 2" wide over the tear. then a seat cover to cover it up. vinyl is nonporous so weatherstripping adhesive would work and it's readily available.

if it's a woven fabric, the adhesive patch thing would also work but you'd feel the bump under the seat cover. if you want to attempt to sew a patch over a tear in woven fabric, you'll need to treat the edges of the tear so it won't ravel into the path of the stitching. run a bead of glue along the fuzzy ends of the fabric along the length of the tear so the abrasion and tension on the cushion won't make the rip continue to grow.

a craft or sewing store is a source for a specialty needle that looks like a U. i've used one before to stitch closed a tear in some headliner. won't be a pretty sewing job until you get the hang of how to control the needle but if you use seat covers, that part won't matter.

good luck to you.

If you have the ability/skills to remove the seat cover (this requires removing the seat from the vehicle and disassembly), you can turn inside out and use the iron-on type of denim patch. If you pull the tear together and iron on the patch, this will create a durable and clean looking repair, make sure you use enough patch to extend an inch or two beyond the tear in all directions. Be careful that you do not use too much heat, just enough to melt the plastic adhesive on the patch into the cover. Removing the seat cover isn't that difficult. Most manufacturers use hog rings to crimp the cover on to the seat frame. You can buy new hog rings and pliers for about 5 bux at most hardware stores. You may even be able to remove the cover without removal of the seat. This is also a good time to wash your seat cover, just make sure you let it air dry (no dryer).
Don't use duct tape as the adhesive will migrate and create a sticky gooey mess that will get on all of your clothes eventually.