An overarching question

You should probably discuss boundary setting with someone you trust. This situation might be only one part of a broader issue with your relationship with your parents, and you can probably make that relationship more beneficial and less detrimental.

Moving out

Once you are legally and financially able to, you could move out (or take action to improve your financial situation to make it more likely you'll be able to do so in the future). Distance can allow a relationship to change to your benefit. It seems that the majority of adults in the wealthiest countries don't live with their parents: http://static3.businessinsider.com/image/5908feb9fcd8eb1e008b4681-1200/young-adults-living-at-home.png https://64.media.tumblr.com/42facc68776260a335473a2553bb7f59/410ac9df6d9c28a0-9f/s1280x1920/8be58d13087dc686c9edcab713f63fc4c538e99a.jpg

The law

Note that, unless you have another reason to not want to be around your parents, I doubt that involving a state institution (like child protective services, a police department, a prosecutor's office) in your relationship with your parents will be helpful. Knowing relevant laws is more useful to better understand what is socially accepted behavior, and to be able to know what public institutions are available to help you if you find yourself in a situation where they're likely to be helpful.

Also, consider whether it's appropriate to tell other people you know about this situation. If you do choose to discuss this with other people, I would follow an escalation procedure so that information doesn't need to spread farther than necessary (for example, tell friends first, then if you don't see improvement tell adults that live near you, then if you don't see improvement tell adults in positions of responsibility (like teachers), and so on).

Privacy

You could inform your parents that state institutions might become involved if they cause you to be recorded while in your bedroom without your consent:

in many places, it is indeed illegal to put cameras in your child's room without their knowledge or consent.

property owners face some limitations when attempting to install cameras throughout a rental property. All cameras must be visible; hidden or spy cameras are not permissible in a tenant’s residence. Similarly, CCTV cameras are forbidden in bathrooms, bedrooms, toilets, and other private areas throughout a rented unit.

These quotes are discussing cameras, but I expect the same laws and principles apply to audio recordings.

If you receive mail to an address and are an adult, I expect you have rights similar to that of a tenant.

Money

It seems your parents cannot force you to buy anything, and surely not an amazon echo. They may have a right to receive money you gained as a compensation for services (as wages) during minority for some reason, but otherwise what is yours is yours, and your parents should only use what is yours in order to promote your interests (like your health, security, and so on), and probably they should only do that when it's necessary (in situations where there is a clear and urgent need).

You may want to ensure you have deposited any money you have acquired into a bank account you own (so there is a record of how long you had it, so it would be more questionable if they tried to claim it isn't yours). It might also be useful to use a separate bank account to receive and account for wages (since it seems there are special exceptions for wages, so keeping clear records of what money is wages and what is not might be useful), and it might be useful to have a UTMA custodial account (like one described at https://www.fidelity.com/learning-center/personal-finance/custodial-account-for-kids) (to enable making it even more clear what property has been transferred to you) (note that this does allow a custodian to use the property, but only for your benefit) (note you probably can't "transfer" money to yourself, so any money you already acquired should probably be managed without using a UTMA or UGMA account).