Glyphosate is the active ingredient in many non-selective weed killers (herbicides) that are commonly used in residential settings. Selective herbicides kill specific plants or families of plants and leave other vegetation unharmed. Non selective means that it kills most of the greenery that it comes in contact with.
Roundup was the first glyphosate based herbicide. It was first introduced in the mid-seventies – developed and patented by a company named Monsanto. For a very long period of time it was the only real option available. The original patent expired around 2000 and there are now several more cost effective options of glyphosate herbicides to choose from.
Farm supply stores (Tractor Supply & Rural King locally – there are others) are good places to find alternatives to Roundup. Drexel Imitator Plus, Pronto, Ranger Pro, and Gly Pho-Sel are some common examples. When shopping for alternatives, look for items with a 41% active ingredient (glyphosate). A similar product may very well be 30-70% cheaper than Roundup.