Place to get rain gear/ water toys?

ok so I have to go to a party where we're going to have a big water fight with water guns and such and I was wondering if anyone knows of a place I could get a cute raincoat and/or a place I can get water guns, I went into walmart just to see what they had, but I couldn't find any water guns and they had the trash bag looking ponchos, so that didn't work for me, thanks in advance :)