Depends what sort of ribbon you want and where you live I guess. Ebay is always a good start if you search for exactly what you want, but be aware that the price shown will vary, sometimes per metre or multiples, sometimes per roll. Also have a look at www.CraftyRibbons.com and www.simplyribbons.com they both have bargain sections and sales! My local market doesn't have a haberdashery stall but I found reasonable priced rolls of ribbon in a garden centre that has a craft section.
I need to buy a considerable amount (yards and yards) of ribbon. Is the market the best place? There is only one craft shop around here and tbh it is pretty dear. Can you recommend an online supplier? Or is Ebay the way to go? Any advice much appreciated, thanks.