Can game developers ask for money from beta testers

Yes, game developers can set just about any terms of use that they want for the right to be a beta tester. They can ask you to pay for access, or allow donations. However, they cannot force you to pay an unannounced fee for past usage if they did not indicate that they would be collecting. They can set a fee for continued usage, but they cannot charge for time that was free when you used it.