Look, thirty bucks for a ridable bike is pretty good. I believe the Sport 500 was at the bottom of the Panasonic line, with the various DX models above it, topping out at the estimable DX-5000. Panasonic made nice bikes, and Japanese bikes are undervalued by collector fools like me, who prefer Euro and Amero trash.
Fix it up a bit-- new grease, bearings and cables, and you'll have a nice ride. I'd say if you enjoy it, and it gets you from A to B, thirty bucks is an excellent buy.
"It's always darkest right before it goes completely black"
Waste your money! Buy my comic book