My bike needs new clutch plates I have found one or two brands varying in price from 55 to 75 is there a difference and can anyone recomend a brand or a website to look at?
There may or may not be a difference in the plates. In all reality it doesn't matter too much on a bike like the GS500. You can spend as much as you like on Carbon Fiber Unobtanium Composite clutch plates, but it will behave and ride just like it would with the cheapest OEM replacement plates.
Save the extra bucks and spend it on beer to celebrate a new clutch job. :)