As a professional graphic design, I see a lot of people trying to pull a lot of stunts. I've seen my share of attempts to get design for free or at a very reduced level. I wish I could count the number of times I've heard the line, "We're just starting out/cash is tight now/I don't know how good your going to be(ie. this is your audition)... but there's a lot of work we'll need to be done soon/next year/down the road and we'll be able to pay much more/quicker/full freight for it."
To my nieces and nephews, you need to learn this lesson. This is a sucker punch, and they're trying to make you the sucker. This ploy is attempting to play to your greed, and it's being made by someone who believes you're just as greedy as they are (and they are very greedy). I can count on one hand the number of times this deal has actually turned into more work down the road. And that's if I include everybody I know. Unfortunately I would need a slide rule to come up with the times this has lead to either no payment at all or late payment.
Now, I have no problem doing some probono work. I have one job in right now. However, when it comes to this type of work, I do what I love, and I do it on my schedule. I have also done a lot of work for minimal pay, but I've gone into the job knowing this (however, I have been debating my policy of having a basic "job fee" and charging just that level for certain jobs and am thinking I'm going to a straight hourly rate/full quotes).
In this economy, never delay payment to you. Don't ever believe someone when they say they would like a hamburger today and gladly pay you next Tuesday. That is unless you're in the loan business or hold a great deal of leverage. When somebody offers to pay you a small sum now, in exchange for a large sum tomorrow, understand that the sun will not come out tomorrow. The person on the other side of the table has no intention of paying you more, or if they do will probably not be in that same position when the bill comes due. Chances are they're trying to play you for the sucker, will take your hard work and walk away.
In related news, Gov. Kasich's budget includes no money or mechanism to institute or cover merit pay for teachers. Same in Wisconsin. Same in Washington DC. Same in NYC.