Cut a patch from a shower curtain and use PVC pipe cement from your dad's garage to patch a leak in a PVC air mattress, inflatable boat, dry bag, etc.
Garbage Santa will reward you for learning this skill.
He'll put all kinds of nice inflatable stuff out at the curb for you.
Step 1: Inflate
Air mattress inflation blowers are now superabundant in thrift stores in the U.S. I think I paid $2 for this one that comes with alligator clips for 12 volts.
Big airmattresses often have a big deflation cap and a smaller inflation valve. I usually use the big cap.
One handy trick to know is the mattress inflates a lot faster if you blow the air AT the big intake instead of IN the intake. That's because the air jet from your blower entrains a bunch of surrounding air and sucks it into the mattress along with it.