Clean out an ice chest. Fill with 130F water. Put steak in a ziplock bag, submerge in water to squeeze out the air, seal ziplock, submerge in the hot water. Put a thermometer in the water, add hot water to keep it at 130F as needed, won't be necessary to do often with a decent ice chest. Wait a couple of hours, remove steak, use a blow torch to sear it.
Sous vide on the cheap.