"Congratulations! You now officially have more IKEA furniture than money".
Mention a detail they are excited about, like a new kitchen or garden. what to say when someone buys a new home
If you want to keep things simple and sincere, focus on the joy of the achievement and the future memories they will create: "Congratulations
"Here's to fresh starts and new beginnings in a beautiful new space". use a classic like
"Welcome to the neighborhood! We hope you love it here as much as we do. Stop by if you need anything".
If you're stuck, use a classic like, "A house is made of bricks and beams; a home is made of love and dreams" — Ralph Waldo Emerson.