As you carry the last few boxes out of your house and set them down in the driveway, you survey your table space. Oh no! You've only got one corner of the office desk left. Running out of usable table space is a common garage sale problem, especially if you've ruled out the use of tarps as alternatives, but there are plenty of options that are far cheaper and easier than buying or renting more tables.
You can start by borrowing tables from neighbors and friends. It seems that everyone has one of those grimy, mossy lawn tables that never get used, and if you offer to clean it off, a friendly neighbor probably won't mind lending it to you for a weekend. Card tables also work, though they tend to be unstable, so avoid putting any fragile items on top of them.
Now, it seems, you've drained the neighborhood dry of usable tables. What now? An old garage sale trick is to remove the doors from your closets and set them up on chairs. These makeshift tables are wonderfully sturdy, and with most doors it's a simple matter of pulling out the hinge pin and rocking them out of their sockets. Folding chairs are best to make door-tables with, as they tend to have seat areas that are both wide and long, providing optimal support.
Similarly, you can rig makeshift tables out of boards supported by chairs or stacks of cinder blocks. Boards narrower than two feet probably aren't worth putting up unless you're in dire need and have nothing else on hand; similarly, boards wider than three and a half or four feet will be tough to support unless you use more than one chair or set of cinder blocks.
If you have a bedframe with a solid surface where the mattress or box spring goes, you can place this out as a two-sided table for people to walk around. This works best when you have a bed with no headboard or a lighter frame that won't require a lot of grunt work to get in and out of the house. Also, make sure it's very clear that the bed is not for sale, or you'll end up with a disgruntled bed-shopper!
If worse comes to worse, you can set up a tarp to place items you don't want to get dirty but that are okay on the ground. Although the most obvious item to put on a tarp is clothing, you might want to avoid that for the sake of your shoppers' backs. Toys also work, as long as you don’t mind kids walking around, over, and on them, because the little ones are already low to the ground.
When you're pricing your items, take stock of what you have and how much space you'll need so that hopefully you won't run into any of these problems. And don't forget to check out GarageSaleCow.com for all your free listing needs!