To make dreams come true, if they aren't gigantic, world changing ones, your magical ally is the time fairy. It's tough to be of the age where you know what you want to do and how you might want to do it, but you don't yet have the ways to earn the money to make small dreams come true.
Where I am, you can get a part-time working with the public job at the magical age of 16. It's that 13 to 16 age where you can figure out things, in every detail but where to get the cash. There was no money for luxuries like fishtanks til I could work in my family - my parents were probably like yours are - generous but stuck in a situation.
I was lucky in that people gave me leaky old fishtanks, and they could be fixed. But they were small and as low tech as you can imagine.
The problem is that once the time fairy's on your side, he/she/it never lets up, and gets more and more generous with speeding things up as time passes. So maybe enjoy that period of life before you go out to work, and slide some of those aquarium ambitions a short couple of years into the future. Now is the time to read about fish and tanks, so you can be ready when possibilities become independent choices.
If you can swing it though - I had scrap glass from old windown for covers - lights sitting on them, homemade filters, the DIY works. Actually, I bought custom cut covers for my killie tanks 2 weeks ago - the first time I've had that in decades. If you were in this part of the planet I could offer you some scrap glass 'cut by me' covers!