How high should it be for 0.0079892 btc? I tried everything. Up till it gave me a warning that the fee was really high.
(I tried to spend 0.004btc) So unfortunately including random fees also doesn't work.
If you're not in a rush, 1 satoshi/byte is enough. The total size will depend on the number of inputs, but I think a 0.00002
BTC is a safe guess to set as fee.
Last time I used Coinb.in, you needed to manually allocate all funds. If not, the remainder will be used as a very high fee. So try to send 0.0079692 out of your 0.0079892 to your own normal wallet.