the best after market warranty
The question is far to general. Do you want bumper to bumper coverage or just engine and drive train. That will seriously affect your cost. MANY of these companies sell VERY questionable products. If you try https://www.autowarrantyagency.com/ I can not guarantee it is the lowest price - but I think I can safely guarantee you will never have any claim issues. If you do a Google search - you will find they have consistent high ratings. CarChex (also very highly rated) sells the EXACT same product - just at a higher price. Other factors such as make/model of your car, current mileage, length of coverage desired, state of residency also play into determining your cost.