Here's a recipe for weed-killer that has the power of Roundup for a fraction of the price. Mix 2 cups of ordinary table salt into 1 gallon of white vinegar that has 5 percent acidity. Add 8 drops of liquid dish washing soap.
Label it, and keep it out of the reach of children. This is not toxic, but it will kill any and all vegetation, even the good stuff, so be careful where you spray it.
Another caution: Spraying this multiple times in the same area will sterilize the soil so that nothing will grow there for a long time. It is ideal for killing weeds that grow between cracks in your sidewalk and other areas where you don't want vegetation.
I think I'll whip me up a batch and spray the brick path in my front yard!