1. A smooth bottom cage. At least 24" X24" (per) guinea pig.
2. 32 oz water bottle
3. Heavy medium to large food dish.
4. Bedding. Wood pulp beddings: Carefresh, Celsorb, EcoBedding to mention a few. Wood based beddings: Aspen or heat treated Pine.
5. Some kind of house. Igloo, Wood house, Square Plastic House
6. Timothy Hay (100% vitamin C) NO ALFALFA
7. Pellet food created for guinea pigs. A good basic pellet. No seeds or colored treats. Oxbow Cavy Cuisine, Kaytee Timothy Pellet, Nurtraphase. NO RABBIT FOOD
8. Timothy hay cubes to keep teeth at proper lengths.
9.Toys: paper bags, toilet paper tubes, cardboard boxes, oatmeal containers, bird mirrors, bells or a stuffed toy (small) with no buttons.
10. Salt lick. NO MINERAL LICKS
What Not to Buy
Plastic Tray Liners
Mineral licks, they are great for rabbits, not for guinea pigs.
Wood block chews, gnaw bones or wood blocks. Guinea pigs like to chew what they can eat. They do not have a great capacity to spit things out and chewing these items
Exercise wheels and balls - these are very bad for guinea pig's backs.
Books to consider
Any Book By Peter Gurney, this man is the guru or guinea pigs out of England! He has several wonderful books available!
What's My Guinea Pig?: A Guide to Guinea Pig Breeds
Proper Care of Guinea Pigs (Proper Care of...Series)
Guinea Pig (Collins Family Pet Guides)
The Sex Life of Guinea Pigs
*New* B81 More of Their Kind
B80 'All of Their Kind
And he is the primary inspiration for the creation of Cavy Care Inc!
Diseases of Domestic Guinea Pigs (Library of Veterinary Practice)
by V. C. G. Richardson
A "must have" book for all cavy caretakers and companions.
Anatomy of the Guinea Pig
by Gale Cooper, Alan L. Schiller
Your Guinea Pig : A Kid's Guide to Raising and Showing
by Wanda L. Curran
Guinea Pigs (ASPCA Pet Care Guides for Kids)
by Mark Evans