Mosquitoes don't inject venom, just their saliva, which causes an allergic reaction. Hence the swelling.
You can actually develop an immunity to their saliva, which results in no apparent effects after being bitten - but it requires one to suffer through a lot of mosquitoe bites...
Sooooooo! Not a hot deal - just go get bitten a lot - then you'll never suffer from swelling and itchiness ever again! Why spend $18?! J/JK
Seriously though, good post perfectlysane
***EDIT***
Mosquitoes home in on carbon dioxide, so as long as you don't breathe, you won't get bitten.