Buying

Where's the best place/way to buy a collection of random metal fight beys? I'm just looking to get a small collection of random beys as cheap as possible. Would buying individuals be better for this or is a collection the right way to go? If buying a collection is cheaper, what's a good way to assess the collection for a balance of types and quality beys? If buying individuals is better what would a good mix of ~10 beys be?
Purchase Consultation thread. Please find it and ask there.