Anyone know which brand is the most cost effective and how much it may cost for that size ?

You should screen and approve every occupant.

They're seldom home during the day and on weekends.The upstairs tenant texted me yesterday (I do have a separate phone line for our properties) saying she's having noise issues with the downstairs tenants: banging the screen door closed after she's gone to sleep on weeknights (11:00pm), talking on the phone at 1:30am, up and about at 2:30am on the weekend.

Lubbock has a low barrier to entry and has several backup economic drivers by being the primary hub (agriculture, financial, healthcare, material goods, transportation, entertainment) for an area the size of most states east of the Mississippi.

I compared size, amenities, whether or not a property was rehabbed, parking, and location.

Originally I was also hoping to find a package that would do more of the property management basics for me, like running ads, screening tenants, collecting rent, collecting e-signatures, etc.What I found after months of looking is that there is no one-size-fits-all platform out there.

A screen shot with the URL and date at the bottom is necessary.

Make sense about spreading costs out more, and building bigger since you'll always have the costs of the foundation, roof, etc regardless of the size. 

I do not have a sheet but I typically budget $150 for lawn, $150 for pool if applicable, $100 for cable, $100 for water, $300 a month for electric (depending on property size and your local utility costs), $50 for pest control, and another $200 per month in misc. 

If doing it yourself, have a plan for showing and screening tenants.