Paying for the crib

So my husband and I bought a crib off Facebook marketplace a couple weeks ago. Yesterday my in-laws were over and his mom sees the crib and offers to pay us the $50 that we bought it for. We said it's no problem, if she wanted to get us something she can pick something off our registry. My husband tells me today she said she may just give us the $50 and I know it sounds like she's just being nice but I know it's because she wants to have "claim" on the crib and be able to say she bought it. She won't settle for a different item, she HAS to pay for the crib🙄 anyways, not being ungrateful, just a little rant