Answer:
It depend upon some points. Explained below.
Step-by-step explanation:
For the given situation i come to the point that some key reason to buy application 
- It should be good for core competencies .it should be good for IS service
 - Time should be available
 - All the professionals have training , experience or skills
 
So to buy application decision will depend upon such that
- cost 
 - availability of resource
 
that may be technical and human and etc
- Application should be compatible in the environment
 - Offer opportunity for strategic focus