I will be looking for a western saddle a little later... as on price, maybe look on the net for the same brands, if they are branded...
They arent measured the same as english...
Check out this site for measuring the seat size...
http://www.cowboyway.com/HowTo/MeasureSaddleSeat.htm
a few other things to look at...
http://www.horsesaddleshop.com/how-to-measure-your-saddle.html