Puddle of Anti-Freeze/Coolant under thermostat, can it be the thermo gasket? I hope? Or is it more than likely?

the head gasket? I just purchased it for 1k, and after actually looking at it, there is a small puddle of Dex Cool just under the thermostat. I cannot see good enough with or without light to tell where it is coming from? I'm praying that it is the Thermostat Gasket. There is NO oil in the coolant and NO coolant in the oil. No smoke/steam from exhaust. What is the cheapest, most quick diagnosis? Has anyone else had this particular issue? Also, on occasion my power windows won't work... just quit all of the sudden then works again after few minutes. Happened twice. I am trying to get on my feet after a downfall in 08 like most people, only I was/am a little bit younger at 22... I'm in bad a sort of bad situation, no job, no place to live, trying to get in college and find a part time job... I don't need this. Any help is greatly appreciated.