There's definitely hope for you. I know from experience that you can made a pretty good medic cosplay with next to no money (I'm broke as shit 100% of the time.) Especially if the con isn't until August. As long as you're willing to make everything yourself, take your time, and stalk some thrift stores, you can totally pull it off. The supplies for making medic's props aren't very expensive. The boots will probably be the most pricey part, unless you can thrift them. I can't tell you much about Heavy, though I imagine it's much of the same philosophy.

Dang, this is way easier then I thought thus far... I already have 75% of the heavy costume done. Your thrift store suggestion helped a TON. thanks Noni!