Yes, there are usable FPV goggles under $100, but understand the trade-offs. Best option in this range: Eachine EV800D ($55-70) -- box-style analog goggles with a built-in DVR recorder, 5-inch screen, 48-channel receiver, and adjustable IPD. Not pretty, but they work for learning.
What you sacrifice vs $120-150 goggles: smaller field of view (FOV), lower resolution display, no head tracker support, and box style has light bleed around the nose. The Skyzone Cobra X V4 Lite (~$90) is a step up -- slim goggle form factor, better FOV, and receiver diversity (two antennas, picks the stronger signal).
At under $100, only analog is available -- digital FPV (DJI, Walksnail, HDZero) starts at $200 minimum. For a BetaFPV Cetus X beginner setup, the Eachine EV800D keeps your total budget manageable.
Check Eachine EV800D on Amazon