Even if stacked under this capsule was the entire mars one stack, you would still need the capsule in case something goes wrong from from T-0 through SECO. Being able to abort and bring people home is a critical element to this.
Once you're in orbit, now you can spin the capsule around, mate it to the transit vehicle, get comfy and head on to mars. In your nice roomy hey let's go to mars bus!
As for what this cost? Less than we've spent bombing ISIS or for that matter what the DOD spent on diesel last year. We MASSIVELY under fund our space agency. Go check this out: http://blogs.discovermagazine.com/badastronomy/2010/02/16/wait-how-big-is-nasas-budget-again/#.VIHeOYqPUyI
It's a joke. We spend NOTHING on our space program. Tests like this are not a waste at all, we need to test these systems before we rely on them.