Securing the bottom plate to a concrete floor?

Get you a few concrete tapcon screws. If you plan to use wood as your bottom plate and your concrete floor is kinda green then use cut nails, if its an older flower that is really cured then use the round concrete nails that have a slight spiral to them plus some Liquid nails glue. The nails are the cheapest way but by all means use safety gles, tapcon screws are your next bet, but the best way is to rent a concrete nail gun, If you go this way just ask the dealer what you are going to shot to the floor, whether wood or metal and he will advise you on which colored shot to us.