You can currently buy pig, cow, chicken, and sheep spawners in any world but BG. The only players who can place spawners are Support Admins or Admins and you will need to open a petition in order to get a spawner.
Pig = $10,000
Cow = $20,000
Sheep = $20,000
Chicken = $40,000
How to request a spawner:
1. Be online and logged on to the server
2. Go to the area you would like the spawner placed
3. Ensure you have the adequate amount of money
4. Type /pe open I would like a (spawner type) spawner placed here. (Be sure to have a wool placed where the spawner goes!)
5. A good example of this would be /pe open I would like a pig spawner placed here.
If no Support Admins or Admins are online you have the following options you can either close your petition by typing /pe close (petition number), or leave the petition open; when an Admin logs on they will place your spawner even if you are offline. They will deduct the money from your account regardless of if you are online or not, so make sure you have enough money!