In my opinion, neither of those two deals is perfect. The going rate for females in general is about $100 per 1000 grams of weight, at least after they reach 1500 grams. I would price your girl between 150 to 170. So, offering 100 for her is quite lowball. Throwing in the tank makes it even worse!
Now, the young female in the other offer is probably worth maybe $60 tops. How much is a male blackback worth? If it doesn't add up to at least 150, I would go with none of the above--hold out for a better offer! Don't undersell just to do it quickly.