Gifts do not confer obligation. If you give me a screwdriver and I use it to run my electrical installation service business, I don’t owe you a payment.

This idea that one must “give back” after receiving a gift freely given is simply silly.

Yes but thank-yous are always good. Making sure the project sticks around is just smart.

If your neighbor kept baking and giving you cookies, to the point where you were wrapping and reselling them at the market, don't you think you should do something for them in return?