Strikeward
Xx_Jagged_Angel_xX
Just step on all of them. That will do the trick. (:
there on my celing, my very high celing
If you think they are coming through the vents, install some vent filters. I know you want inexpensive methods, but spending a little more money does the trick. If you don't, you end up paying more in the long run, like continuously buying repellent every year or something I dunno.
Seal every crack in the house. I dunno about how to kill them when they're in your ceiling but google some methods. Natural and less expensive methods will be better.