I buy 5g tubes of Rema Cold Vulcanizing Cement for $2.25 for my saddle bag which I seem to never use since I swap tubes on the road, I have a Rema 8 oz. ($11.95) can and 100 bulk patch's ($10) that I use at home can is several years old now and still 3/4 full used on 50+ patches over the years many for the grandkids LOL.
If you buy a can and have a few tubes for your saddle bag you will most likely never use the tubes on the road if you are a tube swap person on the road.
Sometimes you find the kits on sale for $1.99 I'll buy them take the tube and save it add the few patches to my bulk box just for the small tube of Vulcanizing Cement.