Talk to the organization you're planning to do your training with. They'll know how it's structured for their program. I'm sure some other folks here know how it works in general.
My understanding is that in general you pay for the PPL part, and the IFR/commercial part is covered by the GI Bill.
I found this on the AOPA page:
I've already started my flight training toward the private pilot requirements. Can I transfer that flight training time over to the sport pilot certificate requirements?
Yes, you may do this. The FAA has clearly expressed that a student pilot certificate is a...
vs. a Private Pilot license?
My ultimate goal, of course, would be the PPL, but after reading here about the show-stopping medical certificate, I'd hate to find out something in that process that stopped me cold from ever even taking lessons! My goal is fun, after all!
So the real question is...
Is it a good prep for the FAA exam? Does the workbook include solutions/explanations? Working on some pre-flight training theory and knowledge.
(In hindsight, I suppose I could have just added this to the FAA prep question below, but too late now...)