How do I cage my baby?

Marissa • I'm just as lost as anybody else • Taking my life day by day

Lol, so I'm referring to keeping my son in one area now that he's crawling (7 months), our house is pretty much baby proofed but for about an hour in the evenings we take him to the garage with us while we workout in our home gym. So far we've just been keeping him in his walker but after about 20 minutes or so he gets bored with it and wants to be crawling, however there's just way too much he could get into in the garage to leave him down on a mat. I've looked at a few baby fences on Amazon but they're pretty expensive. Anybody know of a cheaper solution or even just a cheaper brand fence I may not know of? Just something to keep him in one 24sqft or larger area for an hour or so. Thanks in advance!