Whats my next step for selling a deactivated Iphone 4 on eBay?

I recently bought a sprint iPhone 4 8gb off a person in the mall. The iPhone has a good ESN and is in flawless condition, however she told me that it was deactivated. Usually this wouldn't be a problem because I usually sell lots of phones off eBay all the time, but this time it had no sim card and I'm not familiar with sprint.
My question is can i sell it as is? Because I'm not sure how these kind of phones work without sim cards. I'm assuming I can sell it on eBay deactivated, and when someone buys it, they can call sprint and activate it themselves with no fault. But I just want to make sure is that the right steps to take or am I missing something because I don't want to sell a phone that doesn't work.

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