cad/drawing package question.

Hi everyone.
Can anyone advise me please on which cad/drawing package would be the
most useful for drawing mosaic type tile floor patterns, I would like
to be able to quickly draw repeating patterns from standard geometric
shapes ( triangles, squares, octagons, hexagons etc and change the
colours to suit the ones from old victorian floors.
Cheap would be best for me as I am on a tight budget.
I would like to be able to save them in a graphic type format suitable
for web publishing if possible.
Any advice will be gratefully received.
Sorry if this is a bit OT, hopefully the CAD part wil cover the
question.
All the best.
Gray