You get out of this what you put in. Best low cost option would be to get at least a CFL or a few, a timer, and an oscillating fan and give those seedlings a month inside. They are pretty delicate when so young so putting them outside is risky. They probably won't get enough sun in the window alone. Do lots of reading or suffer a severe learning curve and then get pissed because you could have avoided potential problems but then you'll have to wait a year to try it better.