If I sign a 'work -for-hire' agreement, does that mean I will not make anything if my voice is on TV... maybe even a big TV show theme? They say they would never sell the song but if I do make it big can they exploit that song and make money because of my fame?
If you sing jingles as work-for-hire you will get no payment for recurring play of the jingle spots, known as 'residuals'. This kind of deal is also called a ‘buyout’. Payment is negotiated between jingle client and performer, and you must decide if the fee you are offered is worth it to you right now. Buyouts are frequently offered for local and regional spots. But if you sing larger regional, national and international spots as work-for-hire, you are severely underpaid. (I did that in my early pre-union days as staff singer at a jingle company in Memphis and I know this first hand.)