Pre Design Phase - should I buy the room or not

Hi, members of the best forum in the web, firstly, the room I could buy is perfect for my needs except for some neighbors. But it should be in the city and therefor neighbors "have to be". budget: 40.000 eur The room alone is now slightly above my former upper limit (20000-30000). It costs me 29900 + ~3500(taxes etc.) = 33500 Now I ask myself whether I can sound proof the room with the remaining ~6500eur. Whats the room for: I want to have a room for my recordings, for monitoring music and for bands to practice. And I would love to do all this also at night! A control room could be build later on in the second half, in some years maybe (don't need it at the moment, and I want to spent the money for the things I need ;) ). The pictures: i have inserted the measurements in meters and feet. the cool thing with this room(s) is their height. Its ~4,8m = ~15,7 ft!! I would really love to have such high rooms to build in. My question to you: Is it possible to achieve proper sound isolation for a 30square meter room (~350 sq ft) with ~ 6500Eur? I never did it before. I have to decide whether I buy it or not until next week and I would really appreciate any comments. Especially from all the members that have build a "room within a room" and know about the costs I would never think about at the moment. I have started to fill an excel sheet with data I've found. I attach it here. Maybe anyone could comment it or add some entries. Its only material costs for the inner room at the moment. Later on I will add stuff for room acoustics. Any overall knowledge about the financial part and any approximation for my room would be great. I would love to hear from you ;) Best regards Andy

Thats the current version of my naive assessment (MSExcel). best regards Andy

to be very short; yes 6.500 euro can be the budget you need to soundproof a 30m2 rooms. It's tight tho. But, it kinda depends on yer needs (ofcourse)