Old buddy gave me this recipe:
One gallon household vinegar, one pound table salt. Bring the vinegar to a boil, then dissolve the salt into the pot. Allow to cool, then put it into your sprayer and apply to the soil and unwanted plants.
When I tried this I used a camp stove in the back yard to make the concoction. One gallon will cover about 100 square feet. Everything dies and nothing sprouts for 6 months to a year. As I recall the cost of ingredients was under $5 and prep time was under an hour, application just like any other spray.
I also like a weed burner torch that mounts to a bulk propane tank. Hit them when they are just starting to sprout. Worked nicely on a small rattlesnake also.