Get a pair of Mammut's Serenity 8.7mm ropes and save a bundle.
http://ow.ly/FhA7L
Mammuts 8.7mm Serenity is the lightest single rope available and is suitable for both single and half rope use. As a single rope it suits elite sports climbers, pushing the very hardest grades, where every gram saved makes a difference. As half or double ropes the Serenity is suited to big mountain routes and alpine climbs, offering excellent security and durability.
http://ow.ly/FhA7L
£275 for a pair of 60m (RRP £390)
60m, 70m and 80m available in any combination.