Here is a little more informaiton about the adoption process:
News
The Prince Georges County Animal Management Division is RESCUE-FRIENDLY! We are pleased to work with many rescue organizations. If you are a 501(c)(3) rescue and can help us get our dogs to safety, please call 301-499-8300 and ask to speak to the Rescue Coordinator. Thank you! Adopting an animal
We are looking for great families for our wonderful animals! If you are thinking of adopting, now is the time. If you visit us and don't find the right animal for your home, please ask the adoption staff about submitting an open application. It gets you approved to adopt without listing a particular animal. Then, when the right animal is available, the application processing time is greatly reduced, since you already completed it!
Not sure were the $120 came from

but here is what is listed on the website:
Adoption Fees
For dogs $15
For cats $10
License (for PG residents) $25 for unaltered dogs and cats
License (for PG residents) $5 for altered dogs and cats
Microchip fee $15 for dogs and cats
All animals adopted from the Animal Management Facility are spayed and neutered before they leave.
Spay/Neuter (alter) fee:
$60 for male dogs
$70 for female dogs
$25 for male cats
$40 for female cats