I hate weeds with a passion in my pastures and hayfields.  I also hate spending money on herbicides with a passion.  But after this year I've decided that spraying is deffinatly a better option than clipping weeds over and over again.  What herbicides are available to give me "season long" control.  Mostly ragweed, pigweed, a few thistles, and more ragweed. I'm a cheap operator so if there are any generics I'd be willing to give them a shot.  Here are the options I am thinking of.
Milestone
Forefront  
Grazon P+D
GrazonNext
Generic Grazon?
24d-banvel
I've been using the 24d/banvel (Weedmaster, Rangestar) when I just can't stand to look at a pasture anymore and it works really well but I don't think it offers residual control.  I'm looking for something to spray early spring that will last.  The worst spots are trampled out areas around water or under shade that will turn to solid spiney pigweed in the summer.
Looking for the best bang for my buck.  I've got a lot of land to cover or I'd just go straight to Milestone, but I don't think I want to see that bill.  Has anyone got any price per acre figures they'd be willing to share. I see people on the internet claiming $5/acre with grazon.  I'll make it through this year, just wanting a plan for next spring.