The cheapest way to improve kitchen flooring is to paint it. Make sure the floor is completely clean and dry first, and then you can be totally creative with the paint. When the paint is dry, put one or two coats of polyurethane over it. You can get many ideas for designs at sites like www.diy.com or www.hgtv.com.
Go to FreeCycle.org to see if some is offered in there for free. I too would probably paint it if there ends up being nothing free for the floor.
You can also paint the floor in an artsy pattern. Try this: www.oldhouseweb.com/
And, don't forget to try regular flooring stores. Most are hurting for business and might sell you overstock or slightly imperfect flooring for less than you can do at the home improvement stores.
This is a page about brown paper bag flooring. Floor coverings isn't the first thing that comes to mind when you see brown paper bags. Torn pieces of brown paper bags adhered to the floor and sealed with polyurethane actually makes for an interesting and unique flooring option. Here is some information to get started.
This is a page about luan plywood flooring. This tropical wood flooring is less expensive than laminates. As an underlayment it is smooth level and firm.
This is a page about faux wood flooring ideas. Sometimes the cost of replacing your current floor covering with real wood can be too expensive. Try creating the look of wood planking inexpensively.
ThriftyFun is one of the longest running frugal living communities on the Internet. These are archives of older discussions.
I am remodeling my house and have run short on cash. We have everything done, but the painting and the flooring. Where can I find inexpensive carpet for a living room and two small bedrooms?