Frankly, it is hard for me to see how disc brakes could be more expensive given the relative complexity of drum brakes, although it seems that most manufacturers have had problems over the years getting a parking brake to work right for cheap on rear discs, which may be why they continue to return to rear drums.
Be that as it may: the fact is that all modern drum brakes are supposed to be "self adjusting," but in fact it never works right in 99% of the cases. A doohickey is supposed to bump the adjusting stars tighter when you apply the brakes in reverse, but it never gets it right and in my experience it is necessary to adjust them yourself every 5k miles or so. In fact, I just bought an almost new 2004 Taurus and it was the very first thing I had to do to the car. Failure to adjust rear drums right results in soft/springy brake pedal, and nose diving tendencies.
To begin with, you should probably pull a drum off, just to see how it works when you tighten the adjuster and more important, to see how you have to stick a second screw driver in the hole to move the spring-loaded plate away from the adjusting wheel so you can go the other way, i.e., looser. This is critical, because to get it right, you are really going to have to feel your way and if you are not experienced, this means getting it too tight first. In theory, the "self adjusting" deal is a little ratchet setup that only goes tighter, and you absolutely need to see how it works in order to be able to go backwards and loosen the setting back up, so you can zero in on perfection.
In itself, pulling a drum can be problematic, since the wear of the brake shoe can cause a lip to form inside the edge of the drum, preventing you from freely pulling it off. The cure here is simply to loosen the shoes way up so that the drum can clear the ridge when pulling it off, but you need to know how to loosen first, which puts you in something of a chicken/egg case. But hey -- go figure.
Assuming you can see and understand the tightening/untightening operation (and ignoring the fact that how this setup would ever adjust itself is a complete mystery when you see it), you can get down to it. I myself adjust them wheels-on, with a floor jack on the level and un-busy street in front of my house. It is possible to adjust them on a jack by listening to the intensity of the scraping noise made by the shoes against the drum, while simultaneously spinning the wheel by hand, feeling the drag, and tightening the adjusters. But i go a little further. If you do it the normal way, you jack the car up, put it in neutral, and simply spin the tire while adjusting the star to get to the "right" amount of drag and scraping noise. I actually prefer to jack the car up, tighten the adjusters a few clicks, drop the car back down, and simply push it by hand in neutral to see how freely it coasts. I like it to coast freely with ever so much drag that it stops slightly shorter than when there is no detectible drag at all. Then I'm done.
Either way however, you will quickly see that also being able to loosen the adjustment is critical, because you will always get it too tight on the first try. But once you zero in on it, you just need to add or subtract a few notches on the adusting wheel to get it perfect. And when you do, you will be rewarded with pretty good braking, that is level and straight, and a fairly low hand brake, all without unnecessary drag.
It ain't rocket science and you can do it. Just make sure you know how to loosen the setting as well as tightening, and pay attention to the possibility of too much drag.
Good luck.
