I the only ones I know cost a lot but I have used a more time consuming method to prove factories wrong many times.
Most of the time (in my world) the leak is around the compressor,sight glass, filter drier, because every body is scared of to much heat on install from the factory?
Cheapest option is a glove and a piece of tin foil and trace every piece of pipe and do a 360 of every joint with the tin foil.
Even shutdown without any refrigerant pumping there will be a wet spot somewhere if there is a leak.
If you can pump it up with compressed air then use a squirt bottle with dish soap to look for soap bubbles?
There is nothing cheap in the R world.
I have done some ammonia chillers that will find an imperfection even though you have jumped through all of the hoops to pass everyone's test with no problems?
Give it 7-months it's gonna find something?
If you have a leak then the cheap ones will get you to the area and the expensive ones will put you right there,
If you know how to use them