Jon,
I have been checking into this pretty hard...Below is what I found...
IF YOU ARE THE MAIN ACCOUNT HOLDER : (The first line on the account)
1 Year into contract you can get the phone (in this case Droid) for $199 (after 100 MIR)
2 Years into contract, you still get the phone for $199, but you can get additional savings (in your case, if they shipped you 4 $25 cards, then you could use them toward the purchase price and end up paying $99 after MIR.
IF YOU ARE A SECONDARY LINE HOLDER (like me) : (Additional line on the account)
If you are 20 months into your contract, you can get the phone for $199 (after $100 mir).
If you are less than 20 months into the contract, you have to pay full retail UNLESS...
Another number on your account is up for an upgrade. You can upgrade their phone (including the $29/mo internet upgrade), then they will immediately transfer the phone (and the $29 internet) to your phone.
I have verified the "upgrade using another number's upgrade on your account" with 2 Verizon stores and a telephone rep.
I have not verified that it can be done at a Best Buy store, but I plan to check on that tomorrow.