<human>: Hello!

I run a small-time Youtube channel about video games and such. A few months ago I held a contest for a logo design for my site, promising the winner a sealed box of Magic: The Gathering cards (retail of right around $100).

After picking the winner, he and I worked together over the next day or two, to make any tweaks and such. When it was all done, he sent me all of the original photoshop files. He then asked if, instead of a box of cards, I would give him $100 gift card onto a card-selling website, to do with what he wanted. I offered to simply paypal him $100, so he could literally buy whatever he wants instead of being limited to cards. He agreed, and I paypal'd the money.

I live in SLC, Utah. He lives in California.

I've just been using this logo to brand my videos so far, but I was wondering: if I want to make t-shirts, stickers, stuff like that, and sell them, can I do so with this logo? I have our facebook messages back and forth, but we never really got into those kind of specifics.

If I start selling merchandise with that logo, do I legally owe him any of the money that I make off of the merchandise?

Let's say I end up making a good deal of money off of the merchandise, and I decide I want to send him a "thank you" gift. Does that change anything?

Thanks for any/all help!

Summarize the given text in a few sentences.
<bot>: Held a contest for a logo, paid the winer $100. Can I use the logo to put on merchandise to sell, without legally needing to continue to pay the original artist out of what I earn?