Suggestion 2: Tinker coins & stores.
Tinker coins are a way to buy Tinkercad sets. For example: City blocks, #1: Cost: 600 tinker coins. Premium member cost: 243 tinker coins. A shop can give you blocks to buy so you will have enough blocks for your creation. Each item has a cost. Maybe you should even add a coin store. Examples: $0.99 for 50 tinker coins. $1.99 for 150 tinker coins. $7.99 for 700 tinker coins. $9.99 for 1,100 tinker coins. $10.99 for 2,000 coins. and $24.99 for 6,000 tinker coins. You can even publish your part collection creations and they will go to a model store after you set a price. It starts with a certain amount. There is a minimum. the minimum for 1 block is 3 coins. Colors are worth Nothing! All models have a price. A world with 100 likes through 499 likes means the world is Elite and you pay 1 tinker coin to copy. 2 coins to remix. A world with 500-900 likes means the world is hall of fame.2 coins to copy. 3 tinker coins to remix. Legendary worlds have 901 likes or more. 3 coins to copy, 4 coins to remix. You can tell if your world is elite, hall of fame, or legendary by earning coins. Elite means 100 coins. hall of fame means 250 tinker coins. Legendary means 300 coins. Featured worlds have green borders. Featured world means 200 coins. Featured world: 1 tinker coin to copy. 2 coins to remix. That's all for now.