Fred,
The following is not an endorsement, paid or otherwise...
My single axle EZ-Loader trailer came with surge brakes, but they were totally rusted up and inoperable. I found Champion Trailers
http://www.championtrailers.com/ and bought galvanized replacement drum brakes, new brake lines, a new master cylinder, and a wash-down attachment to wash off salt water from the inside of the brake mechanism. I ended up cleaning, replacing, rebuilding and learning a good little bit about surge brake systems.
I like the way surge brakes work, particularly with my new Toyota Tacoma. It's nice to have the trailer handle some of the stopping chores and not have to rely on the truck alone; particularly with a fairly light truck. When I put on the brakes I can feel the surge brakes on the trailer kick in about half a second after I step on the pedal. Nothing dramatic, just a little change in the hauling load, and it tracks straight with no wobble or wiggle.
Champion sell new couplers as well which you'll need if your trailer doesn't have brakes at all. My trailer (which from previous discussions sounds like yours with the old roller that fell off) uses the Dico/Titan Model 60 coupler. They have a lot of on-line educational information that I found useful, particularly since I've never very done much brake work before.
If you've got a grand to spend on brakes and don't like doing that kind of work, your estimate sounds reasonable to me. If you'd like to do it yourself and save some bucks Champion Trailers can be most helpful. I did it myself 'cause I'm cheap and I also want to know how all of my boat and boat-related systems work. Brakes aren't something to do a halfway job on, but the mechanisms and operating principles aren't too difficult. Heck, even I got the job done right.
Oh, and another thing... Drums vs. discs. I was all set to install disc brakes on the trailer since all the information (sales mostly) on the Web referred to discs as an upgrade from drums. More in-depth research explained to me that the operating mechanism of the disc brake requires more inertial pressure than does the drum brake. The more the trailer weighs, the more inertial pressure you'll get on the master cylinder (which actuates the brakes). I don't remember the details any more but I found that for disc brakes to operate effectively one needed more trailer/boat weight than I felt I had. I've got an '84 Classic on a single axle trailer which weighed in at about 3850 lbs.; perhaps within the reach of disc, but not enough for me to be comfortable with it. Anyway, here's the URL for their article on the subject
http://www.championtrailers.com/DrumVsDiscBrakeArtcl.htm
Good luck.
Tom Herrick