Safety glasses are worth it, I'm recovering from a non-related eye injury from a random bad-luck event, it sucks.
I ALWAYS wear safety glasses, and the prescription Wiley-X ones were expensive but they're comfortable, offer great protection without the eye cups and damn near perfect coverage with the cups, I wear them for riding my motorcycle, shooting, and at work (industrial facility) ... they've caught road rocks, brass, sprays, and lots of "what the hell was that?!" objects ... so far the only thing to damage them was a .45 casing that hit rim-first, which left a small chip in the finish.
Think on that, a .45 casing's sharp edge did more damage than road crap at 75mph does ... get some glasses with good coverage!
And bullet bounces happen with a dirt berm, there's rocks in there, there's BULLETS in there, and something will bounce back if you keep trying.
If the expensive goggles are too much, pick out some nerdy-looking glasses with sturdy rims and z87-rated polycarbonate lenses, and add side shields ... coupled with a cap that will offer decent coverage. I'm probably not cool enough for the Wiley-X goggles, and I admit they were expensive (adding transitions lenses was worth it, though!) ... but they're about as safe as it gets with a single layer of coverage.