A lot of folks in the prosperity gospel movement glom on to Jeremiah 29:11, from the NIV.
First of all, if you look at the original text, where the NIV says prosper, the original text uses the word shalom. You may recognize this as a Hebrew greeting, it means peace. Also, where the NIV says "hope and a future." the original text uses the words "tiqvah achariyth" tiqvah litterally means a cord but is often used to mean "what is expected", and achariyth means end. He's not promising some abundance here, he's just promising peace and a normal life.
Secondly, I believe some things in scripture are specifically said to one person. I believe this passage of Jeremiah is one of those instances.
I've been told by biblical scholars that the American Standard Version of 1901 is the closest translation, word for word, of all the bible versions. Here is that verse from Jeremiah from the ASV.
"11 For I know the thoughts that I think toward you, saith Jehovah, thoughts of peace, and not of evil, to give you hope in your latter end."
In reading the whole chapter, I actually think this was directed to all those taken captive and taken to Babylon. Verse 11 falls after the author states that Jehovah has spoken of the future of the captives. Verse 10 is below.
" For thus saith Jehovah, After seventy years are accomplished for Babylon, I will visit you, and perform my good word toward you, in causing you to return to this place."