Tow Hitch Cover

I'm thinking about getting a hitch-mounted bike rack, but I don't have a hitch and don't know if it's expensive or difficult to install one. I have a towing bumper with the hole drilled in the center. Is there a different type of bike rack I could use without paying for expensive installation?

I don't like to put my bike in the bed because 1) it takes up too much space that I need for other things and 2) I have a bed cover, so I have to take the front wheel off the bike to fit it inside.
99leadpencils, what type of rear rack do you mean for a truck? So far, I've only seen the kind that hooks into a trailer hitch, and the kind that hooks into the trunk of a car. There should be other options for the back of a truck. My pickup has a regular sized cab, so I think that a roof rack big enough to hold a bike won't fit.