Here's one I just looked at, for an example. The first option for this suite is the least expensive (out of pocket). Though it has Freeplay and your deposit comes back to you as OBC. The second one, is about $1,000 more, but has a significant amount of OBC.
Decisions, decisions !
Some of the fine print, for the second offer:
Offer is capacity controlled and subject to change at any time. Promotional deposit of $99 per person is non-refundable for sailings outside of final payment due date. Onboard Credit is non-transferable and is provided as a non-refundable credit to your Sail & Sign account of $500 per person up to $1,000 per room for 2-5 day sailings, and $1,000 per person up to $2,000 per room for 6+ day sailings. count. Onboard credit may vary with single supplement rates. Onboard credit may not be applied to cruise fare or Taxes, Fees and Port Expenses.
Tom