Value of an iphone 5 32gb vs iphone 4S 64 gb?

I have an unlocked iphone 5 32gb (still running iOS 6 if that makes a difference), however, I'm unhappy with it, I preferred my iphone 4 although it was only 16gb. I'd really like to trade mine for an unlocked 64gb 4S so I can have more storage and also have something similar to my old iphone 4. However they are hard to come by so it hasn't been easy finding someone willing to trade. My iphone 5 runs perfectly and has just a few minor scratches and scuffs on the back and around the sides. I'd like to know if one is significantly more valuable than the other so I know if trading is unreasonable. Also, I know of sites that buy phones off people, are there any that offer trading instead?
As a last resort, I'd also be willing to trade in my phone AND pay extra (no more than $100-$200) for a 64gb 5 or 5S as long as they work with tmobile. Storage is really my biggest issue as I'm over 10gb over capacity on my 32gb.

5s is amazing. Definitely get it. I got one myself a while back and i love it. Its faster, newer, cleaner( as I feel like at least) and it has new features…

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