Fancy dress party - wild west

[Beatlesfan]

We have been invited to a do on Sat and I would like to dress Imogen up in Wild West outift. Don't have anything at home that could be used... does anyone hae any ideas/advice on where to buy cheap outfit for 8 month old or how to make one quite quickly, cheaply and easily?

I can;t find a lot of dressing up clothes for babies on the net or in shops. They all seem to start for 3 years olds!

Thanks!