Q: Trade in my 5c question

iTunes gift card. You may be better off selling the phone yourself or seeing if your carrier has a trade in option. I got $200 from Verizon when I upgraded to an iPhone 6s from my iPhone 5.

think the recycle program offered me what would amount to 50 us dollars for my old iphone4 16GB

The online estimate for a pristine iPhone 5c (white, 32GB, carrier unlocked) is $75.00 USD - http://www.apple.com/recycling/

Gazelle.com only offers $50 for the same device.  You can almost certianly do better selling it yourself, but be sure to prepare it properly for sale first:

Read and follow the directions at What to do before selling or giving away your iPhone, iPad, or iPod touch - Apple Support

It is an Apple Store gift card, not an iTunes gift card.