The following accommodation will suit all budgets.

Camping:
Dinas Farm, Tregarth (Phone: 01248 364227) [A]

Bunkhouse:
Gallt y Glyn, Llanberis (Phone: 01286 870370) [A]
Jessie James' Bunkhouse, Penisarwaun (Phone: 01286 870521) [A & B]

Youth Hostels:
Ogwen (Phone: 01248 600225) [A]
Bangor (Phone: 01248 353516) [A]
Llanberis (Phone: 01286 870280) [A]

Self Catering:
Ogwen Valley Holidays, Ogwen Valley (Phone: 01248 600122)
Mountain Studios, Bethesda [B]

Hotels:
Gallt y Glyn, Llanberis (Phone: 01286 870370) [B]
Dolbadarn, Llanberis (Phone: 01286 870277) [C]
Seiont Manor Hotel, Llanrug (Phone: 01286 673366) [D]

Also see the Wales Tourist Board Web Site

Price range per night: A=Less than £20 B=£20-£25 C=£25-£30 D=above £30