If you wanted to buy something, then you will have to talk to NI.
But for what you are describing, you are in luck. This year, NI released a Community Edition of LabVIEW. It is intended for people who want to to those home sort of projects. The best part. It is free. It can't be used for commercial or academic purposes.
See https://www.ni.com/en-us/shop/labview/select-edition/labview-community-edition.html
You do need to register yourself and have it activate a license. But since you have an account on the Discussion Forums, that should already be taken care of.
To answer the other questions, if you were starting a business, you'd have to pay for it. It comes with a year of SSP (subscription service program?) included which is support and free upgrades. But after that year, you'd have to pay the yearly SSP price (a fraction of the full price) to continue the upgrades and support. If you don't renew the subscription, the LabVIEW license you bought is still valid and can be installed on new PC's like if you replace your PC with a newer model.
Of course like most things in life, prices will generally go up year after year.
