Sorry this Is a bit late but this subject is close to my heart.
For under $700.00 (one time cost) you can get a Oly barbell, iron plates, and a squat rack. Get a competent Strength coach to teach you how to perform the basic barbell lifts safely and put together a simple program built around progressing the basic lifts.
Walk on your non lifting days
No gym required. In fact the above is more effective for your health then most anything else you can do in a gym. Not to mention most efficient from a time management point of you.