When a loan defaults, the lender balances the risk of receiving no money, the cost/liklihood of getting a judgment and using garnishment to get their money, and the amount that they feel like they could get from an immediate settlement offer with the borrower. If your loan is still in the statute of limitations, they may be inclined to ask for a higher settlement offer if they know you currently have a job, because garnishment through a judgment is still an option. If the debt is close to the end of the SoL, or past it, they'll probably take a much lower amount.
You can also negotiate the way the account appears on your credit report, so you should ask if they are willing to update the account to positive, or remove the collection account entirely (if there is one) along with the settlement offer.
You can find a lot of information about settlement offers in the Rebuilding Your Credit forum. Private student loans are subject to the same laws as other installment debt (with the exception that it cannot be discharged in bankruptcy(, so you can look at other people's experiences with unsecured debt to inform your plan.
