Purchase price: $270,000 Cash invested: $55,000 2 Bedroom, 2 bath condo, 2 stories, nice centrally located complex with pool and small gym amenities.

I would really focus on educating yourself -- read as many real estate investing books as you can, and listen to a couple dozen episodes of the BiggerPockets podcast (I listen to a couple each week while working, at the gym, or driving.)

Bowling alley or gym.

If some local businesses allow, I would put up flyers in them to market that way too (ie gyms, barbershops, supermarket, etc). 

I use Libby to listen to audio books while in the gym (free with the library card).

Gym/personal training.

The only thing I have seen work in a situation like this is turning it into "gym" space and leasing it at a lower rate.

There was nothing in my life except for family, work and REI: no drinking with friends, no golf, no TV, no gym. 

A lot of professionals who might rent may want that extra bedroom for a home office or home gym, etc. 

You could sell the house for $250,000 and receive a gym bag full of bundled $20 bills.