Will Tmobile let me trade my Samsung Galaxy s4 for iPhone 5, 5s, or 5c?

I don't have Jump by Tmobile because I got my galaxy s4 before Jump was introduced (I think). Really want an iPhone because, even though the s4 is extremely nice, I've encountered many problems with it over and over again.

Probably not.

But the only way to know is to ask them.

Well here is a comparison of the three phones you mentioned above. - I would advise buying the 5s though, its a great phone.