We just bought a hunk of green shadeclothe, we cut a piece off to use under the shower/crapper tent and the rest under the annex area.
We just drive the pegs through and sweep it out once a day.
If it frays, i'll trim it around the edge and when it buggered, dump it, but it seems to cop a hiding ok.
I think.... i paid about $70.00 or sumfin like dat.
The money i save i can put towards camping fees.