Who make the best 737 classic (737-300, 400, and 500) models? I know the 50 North models are very good, but I don't have the money right now for payware stuff, so which model is the best freeware one?

Although you dont mention it, the Tinmouse 737-200 is a superb freeware aircraft. Have a look on the dedicated forum here at Avsim.

 

Peter

If zou are searching for FS9 aircraft you can always use those Eric Canu models which can be found here : http://library.avsim.net/search.php?SearchTerm=vista+liners&CatID=fs2004ac&Go=Search