Meaning of this piece of dialogue in The Call of the Wild?

Here is an excerpt from Chapter 1 of The Call of the Wild by Jack London:

Yet his time came, in the end, in the form of a little weazened man
who spat broken English and many strange and uncouth exclamations
which Buck could not understand.

"Sacredam!" he cried, when his eyes lit upon Buck. "Dat one dam bully
dog! Eh? How moch?"

"Three hundred, and a present at that," was the prompt reply of the
man in the red sweater. "And seem’ it’s government money, you ain’t
got no kick coming, eh, Perrault?"

Perrault grinned. Considering that the price of dogs had been boomed
skyward by the unwonted demand, it was not an unfair sum for so fine
an animal. The Canadian Government would be no loser, nor would its
despatches travel the slower. Perrault knew dogs, and when he looked
at Buck he knew that he was one in a thousand—"One in ten t’ousand,"
he commented mentally.

What does "present" mean in this context?

Also, what exactly does the second part in the bold mean in simpler English?