Shuaib,
There are no other costs involved other than that need to have all client machines covered with SA + MDOP on top of that. App-V Management Server and Sequencer(s) do not cost anything extra (besides the underlying OS platform of course).
Just to point out for the sake of completeness, if you are using App-V in TS environment then new RDS CALs (since sometimes last year?) already include App-V Client license for that environment.
/Kalle
