- The block is full
The chance of that is high.
- There is a high interest to get a transaction into this block
They may or may not be. I don't think having a TX included into that block is anything special.
- You are making a 1 input 1 output transaction
Bad assumption. If we have learned anything, then we know that the majority of the TX's are much bigger. If anyone is wondering how they would create a TX with 1 input and 1 output: e.g. Pick 1 input, send to exact same amount to another address while deducting the fee from the amount (there must be no change).
I'm going to say a 0.0007-0.001 fee
Random numbers don't help.