We get our cabinets through.the box stores.

If you would like to generate your own leads, I would pop over to the the wholesale section of the forum and start there, and perhaps purchase some books from the BP store.

I capture the receipts as soon as I leave a home improvement store and it has saved my butt because those receipts pile up fast when you're in active renovation on multiple properties. 

I would assume a greater emphasis on quality of materials and workmanship (and consequently higher rehab cost) for a rental where the investor will have to deal with the longer term implications of any corners that were cut.

Thrift stores take a lot of time to shop at, wasted time in my opinion. 

I was thinking of giving him 3 options.Option 1: He switches to a month to month lease changing to a weekly rent rather than monthly, the new lease will have different rules (ex. such as agreeing to a cleaning schedule and a liter schedule or trash needs to be picked up and placed in a trash can every 12 hours, human waste can not be stored in containers)Option 2: He moves out at the end of March, I keep the security deposit as rent and he does not have to pay February's rent and late fees.Option 3: I'll give him $400 to move out 3 days after we have this discussion.Thank you for any suggestions, I would like to handle this delicately as I don't want a squatter living with me.

Install a lock box on the property with the key stored inside.

Your pictures do not paint a picture of what I'm looking at.There is a renovated 2bed/1bath right around the corner for $1,050 and it has a decent floorplan.

If they can do something as simple as this what else are they cutting corners on?

Quote from @James Zobrisky: What is everyone's best advice for where to store your cash flow.