GafferTape.com have a sale on of budget 50mm x 50M Duct tape £2.42 per roll + vat ( £2.90 )
Jumbo Box 24 rolls = 62.72 inc VAT = £2.61 per roll
Standard delivery charge is £5.95
So 10 rolls = £33.71 including delivery.
24 rolls = £68.67 including delivery.
see:
http://www.gaffatape.com/budget-duct...e/default.aspx