I'm not certain what's available, but a week or so ago, I decided to purchase a 4 gallon back pack sprayer (big tank on your back; very easy to pressurize.) It was only $70 for a name brand that I trusted. If you're buying the premixed stuff in gallons, that you use the little squirt handle for, getting a sprayer can potentially save you a fortune, if you have a large enough lawn. I had one of those little quarts of concentrated (25%) roundup in my cart. I happened to go into the right area at tractor supply & saw, "whoa. 41%? Multiple gallons of the stuff, for only twice as much??!"
I have a brick patio. Weeds love to grow up in the cracks. In the past, it's taken me about an hour to spray the whole patio. Now, it's 5 minutes. My gravel driveway: another hour. Now, 5 minutes. All the weeds in the flower bed (carefully), etc., just a matter of minutes. And, I barely dented my supply. I'll be helping my son kill some weeds around his lawn (huuuuuuuge) in the near future. Now, I go out of my way looking for weeds to kill, the process is so effortless.
But, one thing that I really learned - info generally hidden from the normal homeowner - the huge supply of roundup lists specific concentrations necessary for practically every weed you can imagine - pages upon pages. Some, you need to mix in 2-4 D to effectively eradicate, etc. Sometimes, it's 5%; sometimes it's 10%.
So, in relation to the weed problem posted above, doesn't quite kill the dandelions, then the dandelions come back, the information on what is necessary to completely kill them, concentrations, etc., is out there. But, for the consumer stuff, they really seem to limit the concentration you use; and it's far lower than the concentration in the booklet for many types of weeds.
Of course, my experience so far is only for areas where I don't want anything growing; not in the middle of a lawn. And, it's pretty easy to go to a farm supply place & pick up "the good stuff." I'm just going to assume "the good stuff" is out there for killing dicots in a field of monocots.