I really like my Olympic bifocal glasses from Safety Glasses USA (.com).
They kind of look like Oakley M frames.
<$30 for a pair; I keep one pair in my range bag and one pair on my reloading bench.
Safety Glasses USA is old school too, you can call them, talk to a real person and make your order.
You will have your order in a couple of days too!
I have no conections with them other than being a past and hopefully future customer.
FM