"Derick said we should put Dr. Pepper on there, because if you have late nights, you have to have caffeine," Jill tells PEOPLE with a laugh." And I told him, 'I like Fanta,' so he put that on there and some Gatorade, as well."
Jill, 23 and Derick, 25, who revealed her pregnancy exclusively to PEOPLE last month, have also considered the more traditional items for their registry.
"It was a really fun date, we had a great time," Jill says of registering at Walmart, which her husband documented on Instagram.
"We tried to think practical since we don't know what we are having yet. I know people are trying to guess, but we don't even know. I came from a large family and my mom used to think – when I'm buying, do I want to go with one theme or be more practical? We are trying to think of gender neutral stuff, trying to think longterm."
The stars of TLC's hit reality show 19 Kids & Counting, airing Tuesdays at 9 p.m., also made news when they selected cereals on their wedding registry.
Back at home, Jill says now that she is into her pregnancy's second trimester, she's feeling much better and enjoying making dinner (sloppy Joes) and plans for the new baby's room.
"We are planning on keeping the baby with us the first few weeks," she says. "We are still trying to decide about whether or not we'll do sleep training, but we will transition the baby into their own room eventually."
Meanwhile, the grandparents are already giving gifts to their new unborn grandchild – or grandchildren?
"The grandmas are really excited," Jill says of her mom, Michelle, 47 and Derick's mom, Cathy, 57. "They are thinking of all the things that a baby should have. Derick's mom gave us two car seats that strap to a suitcase when you are traveling. She said, 'I'll give you two in case you are having twins.' "