+1

and round up is really $$$$$$ when your doing a lot of area and the torch works 100% of the time
thin of it like a brush fire after it burns nothing grows for a long time
You can get roundup for like $18 for 2.5 gallons if you get generic glyphosate (Credit 41, etc) from a farm supply store. Plus, the application rate is like 24oz per acre, so 2.5 gallons of glyphosate will go a looooong way in a lawn.
And for whoever said that roundup is bad if you have kids/pets, you can drink the stuff (I wouldn't recommend it- you'll pee out of your ******** for a couple of weeks), so there's that.
If most of your weeds are broadleaf (read: not grass weeds like crabgrass, johnsongrass, etc), I stand by my previous statement of using 2,4-D which is basically a synthetic plant hormone. It'll selectively kill the broadleafs without killing the grass. I don't know the price off the top of my head, but it's one of the very first synthetic herbicide chemistries (if not the first), so it shouldn't be pricey at all
And people laugh at me when I say I'm going to school for agronomy...