My band is by no means a big band nationally (heck even regionally), but we've been able to snag a few deals. Most have been artist pricing, which is *generally* around 50-60% off MSRP (so only about 20-40% less than street price). I got a "full" endorsement through an amp company that initially gave me 2 4x12's and an amp head, along with an 8x10 for our bass player, and from then on, it's strictly top tier artist pricing. I've also got artist pricing from 2 other amp companies, but in the end did not choose to buy (either due to money or just didn't dig the tone). I've got a string deal where I get strings for around 2-3 bucks a set, roughly half of store cost. Our drummer has a deal with a sorta well known percussion company and he uses their double kick pedal. Our bass player has some artist pricing deals and working relationships with a couple places...
For us, it was a matter of luck and shows. We got an artist pricing deal through the US distributor of Warwick and Framus a few years back (which I think Warwick now has it's own US distro) simply because our debut show was as support for Lamb of God, Unearth and All that Remains. Our bass player knew 'wick was coming out a dual humbucking version of the corvette (the double buck), and emailed the distro asking about release times for this bass, and dropped that we were playing this show (he wanted to have the bass in time to use it that night)....Their reply was "we want as many of our products on stage that night as we can get, so here is a discount", and shipped him a pre-release version of the bass (I think it came out a month or two later). He ended up buying a second one (he has since sold both and uses ESP's now).
Since then, we've always tried to market ourselves to promoters and booking agents as "the" viable local supporter for big shows, and have been lucky enough to play a number of national shows which helped us in other deals. For our "full" endorsement, it was simply because the owner said he dug what we did and wanted to support us...And, I dig their stuff, too, so it worked out!
I think a lot of dudes get caught up in the endorsement game and go about just throwing press kits at every single company they can and just hope one bites. At times I get the urge to do this (whether or not I deserve anything), and I have submitted to the bigger brands I truly, truly like (and been denied). But in the end it comes down to what products you believe in...And, in a sense, it's kinda wierd because the stuff I dig I'd buy regardless, but it would be kinda cool to be designated as an official "hey, I dig this gear" guy!
EDIT
as for Jager, we've played a few Jager shows/tours and have submitted to be a Jager band. I don't think it's too hard to do, something like 6 shows a month is a minimum requirement. I think what they do in return is a bit different for different levels. On the local level, it's usually just a shipment of Jager branded shot glasses and stickers, etc. That seems to be the thing locals around here get.