Visa runs and 90 day visa

Hi. I'm planning on moving to Paraguay. I am able to get a 90 day visa on arrival at the airport.

Question I have is whether I need an exiting flight/bus ticket to enter the country. I was planning on buying a one way ticket. Does anyone have experience with this?

One other question. Any sources of social meet ups? Any expat groups where I can meet people to get orientated. I'm of course interested in meeting locals but I ask about expats just for getting my feet on the ground.

Thank you.