Can cell phones - replacement for lost ones, for example, be purchased
outside company plans?  All sales on line appear to be connected to
plans. Are there exclusive deals between companies that preclude
people from simply purchasing a cell phone at prices more reasonable
than phone stores?

I recently purchased a new cell phone at the local Verizon store
without purchasing a plan. The sales rep pushed really hard to get me
to sign a 2 or 3 year contract but I just kept saying no. The flip
phone, one step up from the cheapest, cost around $120 if I remember
correctly. I did not price shop so I don't know if that's a good price
or not, it is about what I expected to pay.