Have Enough Seats
What if you have five patio chairs and 25 guests? Assess your indoor furniture. The easiest option is to press dining chairs into service, along with any drum stools or poufs. If you’re keeping things casual, you can spread pretty quilts on the ground and let people gather picnic-style.
Renting can be another surprisingly cheap way to go. Folding chairs start as low as $2 apiece. (You may also be able to rent coolers, speakers, tableware, and a bigger grill.) Many vendors will even drop off and pick up, so all you have to round up is the guests and good cheer.