Looking for second hand cages on Ebay or Craiglist would be a sensible option- most of my cages are second hand but are still in great condition
For a syrian hamster you really need a cage that is 80 x 50 cm (which I think is around 590 sq inches).
If you do want a cheaper cage that is still big enough I would also recommend making a bin cage. I have personally made two, there only took a couple of hours and where fairly easy to make. If you search for "Hamster Bin Cage" on the internet there is loads of information about them.
Here is the video that I used to help me!
How to: Make a Bin Cage + Extension - YouTube