$51.99 Rain Bird T63-100 Drip Irrigation 1/2 Blank Distribution Tubing, 100' Roll, Black: Amazon.co.uk 
1/2 Polyethylene Drip Irrigation Tubing 50' (.600 ID x .700 OD) - Walmart.com - Walmart.com
DIG 1/2 in. (.700 O.D.) x 500 ft. Poly Drip Irrigation Tubing-B37 - The Home Depot
