When you enter a game in Roblox, you should first look for the level equipment. That means all those resources like weapons, building tools, power-ups or even cars that you can use to advance in the game.
Of course, some (very few) levels contain microtransactions that make it impossible to get ahead unless you spend real money. So it is important that you read the details before entering a level to make sure that they don’t have microtransactions if you don’t want to spend money.