100 stars costs 1050 diamonds so let's say 300 stars is the competition for your 3k diamonds.
300 stars is likely to get you about 3-4 daily specials. It will also get you at least 30 train tickets which would average to 60 track pieces and 3 grand prizes. So your 9 reindeer have to average out in value to you to 1.5 train upgrades, 4 daily specials you want, and 1.5 grand prizes you have no say in. It'll be a tough call, but for some people the 9 reindeer might be worth it. If at least 2 train upgrades show up, that'd probably be enough to lure in someone to take the package.
300 stars is likely to get you about 3-4 daily specials. It will also get you at least 30 train tickets which would average to 60 track pieces and 3 grand prizes. So your 9 reindeer have to average out in value to you to 1.5 train upgrades, 4 daily specials you want, and 1.5 grand prizes you have no say in. It'll be a tough call, but for some people the 9 reindeer might be worth it. If at least 2 train upgrades show up, that'd probably be enough to lure in someone to take the package.