clearomizers are easiest to use. you get a burn taste, change the head in 5sec. no mess and simple installation. if this is a hassle, all other options will just be more hassle.
saving money on these replacement head is a different story. you can get many more usage of burned atomizer head by dry burning them. if you want to get more mileage out of them, rebuilding the coil/wick is another option.
Wanting to do rba/rda just to save money isn't a good reason. it requires lots of learning and trial/error. not worth it.
However, if you want better flavor and vapor, nothing can beat RBA/rda. It also provides infinite amount of control over your setup. This means, these requires lot (and I mean a lot!) more work to use.
Right its super easy to change the head... My point not every day... That is more annoying to me... It seems for some reason everyone gets more mileage out of theirs then I do...