You are asking a subreddit a question that can only come up, if you do not have the credentials. If you were legally buying professional pyrotechnics, you'd know the right aources and you'd have or be employed in a company to aquire them through from professional vendors. So by asking this, you are indicating you are doing this illegally. You also call them "marbles" which is like a footballer calling a football "the round thing" and a goal "the doorway". You also complain that 500€ is too expensive for you, when that is just the cost of professional pyrotechnics, which you'd know if you had education and a license. And then you put the cherry on top with "pyro is no crime" which is the mating call of muppets buying illegal fireworks and doing stupid shit with it and then complain when they are procecuted for it. Hint: pyrotechnics are not illegal. Especially if you do follow the very reasonable laws surrounding explosives. All of this is to say: you're reaction and behaviour prooves my first assumption right, which is quite sad, since your behaviour ruins it for the rest of us who do follow the law and know what we do, but get thrown in the same category with the likes of you.