There are many levels of furnace filters. I can get cheap ones at walmart of a few bucks. Then there are ones that cost upwards of $30. I realize that if you have allergies or low immune systems, these are probably worth it. Also if you have pets they may help. But for average folks, with no medical needs, are they worth the cost?
The problem with the really cheap filters is that you really should replace them monthly. The slightly more expensive filters often only need to be replaced every 3 months or so, which in reality doesn't actually make them that much more expensive.
I usually go with the cheapest 3 month filters, since I know I'm not going to get down there every month to replace the super cheap ones. Aside from that consideration and the ones you already mentioned, there's no need to spend lots of money on a top of the line filter. They aren't going to make your furnace last any longer.