I'm nobody's excuse for a gym rat or fitness fanatic, so my input may not be that valuable. But if you're on a budget, it's tough to go wrong with a couple-three kettlebells - think 20#, 30#, and 40#, a freemium kettlebells app, and bodyweight exercises. On my Samsung, the apps I use are called "Kettlebell Workout" and "Daily Ab Workout Free"; there are probably different ones on iTunes. Plus, you can bring a kettlebell on road trips if you travel that way for work. Since it's pretty easy to develop bad form and hurt yourself, it's probably worth periodic sessions with a trainer certified to teach whatever type of lifting you're contemplating. I know a kettlebell trainer and will periodically check-in with him to make sure I'm not too far off course.