Heater core, Bit of help Options

[Imawakeyo]

Ok well I know my heater core is no good but like everything I've been putting it off. Now that temps are reaching the 30s i can't really put it off anymore lol. Problem is beforehand, all that happened was a bit of smoke came from the blower motor region every couple days when I put the heat on. Its gotten to the point now that once I turn on any hint of heat, it fogs up all my windows... So now that I'm forced to change it I'm looking for something affordable for a college kid Called up the Toyota dealers nearby and all of them want $300+ which is a bit too much. Being deployed in February so I might have to sell the car regardless, so not really looking for something expensive. Any site suggestions where I can find it any cheaper or are the eBay ones reliable? Much appreciated.