Just be gracious and accept the gift.
I'm not sure where the idea that you're establishing expectations comes from, but that's entirely ridiculous. (I'm sorry that sounds harsh) Is that what you do when YOU give gifts? Are your gifts to others a message that in the future they had better give you a gift of the same value or better if they want your friendship?? I certainly hope not!!
Honestly, I think you're being silly. (Again, I'm sorry that sounds harsh)
You're neighbors are perfectly capable and have the responsibility AND the obligation to take care of their own finances. What they spend is their business, not ours.
Simply write them a Thank you card expressing your gratitude for the wonderful gift and appreciate the extra thoughfulness in the type of item it is. You may choose to mention it being far and above expectation and necessity, but you really don't need to unless it will make you feel better.
My guess is that there isn't anything nefarious about the gift, so just smile and feel blessed to have good neighbors who are so kind.
Hugs