The realtor I'm working with says there most likely squatters in the house (junker cars in the yard, black plastic on the window on the bedroom side, one window is open = lack of power/lack of a/c).I'm still willing to buy to fix up and flip, for the right price, assuming I can either be assured of the property is vacant, or there is a low-cost, efficient eviction process in Columbus, GA.I appreciate any advice from people with experience on evicting squatters in GA.

It's not hard like rocket science, brain surgery, or other things that require an enormous intellect in addition to the hard work. 

I was looking into something like a plastic one from Home Depot/Costco, one that’s sturdy and gets the job done but isn’t too costly.

My neighbor is a LTR and he put a plastic table and chair in his front yard. 

There are also canopies that are made of plastic that do the same. 

When we had our granite countertop installed the installers put sticky plastic down to “protect” the floors, and when it was removed it ripped the clear coat clean off in the areas my daughter had been playing with the air pockets.

anything newer than 1985 I would not bother its probably plastic piping underground. older than that I would highly suggest IT.

Abandon plastic plumbing. 

If it's grease I've had good luck using either the drain cleaner someone else listed earlier or dishwasher detergent with hot water, let set overnight- it's the strongest detergent you can buy, but won't damage plastic pipes (can work on slow toilets as well, since it breaks down, er "food").

The next thing you need to be successful is a good investment team.Investment TeamIf you needed surgery, you would not start medical school.