Some benefits of belonging to a Homeschool co-op include:

Group Learning:

A homeschool co-op provides an opportunity for homeschool children to experience learning in a group atmosphere. Young students learn skills such as raising their hand to speak, taking turns, waiting in lines, etc.  Older students learn more advanced group skills such as working together on projects, class participation, respect for other teachers, and respect for fellow students.

Making Friends:

Homeschool co-ops provide fellowship opportunities for both the student and the parent.  Not only do the Students have an opportunity to make friends, the Parents meet other parents, encourage each other, ask questions, and bounce ideas off each other.

Shared Expense and Equipment:

Some subjects require equipment or supplies that can be expensive for each family to buy.  In a group setting supplies can be pooled and expenses can be shared through homeschool coop classes.

Having Classes that are difficult to Teach at Home:

Homeschool co-ops usually offer classes that require more preparation and clean up than their everyday home studies.