To what standard do you want to test? That is the most important question regarding the price of the Equipment
Sadly, new devices that can certify 1GBaseT really do start at >5000 Euro list price. 10GbaseT or Fiber testers are a couple thousands more.
If this is just a one off test, you should be able to rent a proper tester. Maybe the used market is also an alternative, but to reliably test the device needs to be calibrated.
There are three companies, that i am aware off, that make these devices and have good reputations: Fluke (never used one), Ideal Networks (I regularly use an older LanTEK II at work) and Softing (I occasionally use a FiberXpert). There are surely others, but i am not aware of them.