Try to pump up the tires. You might be surprised.

What size rims? 16"x4.5"?

There's no point in buying 4 new tires unless you plan on keeping and using them. Tires are too expensive these days and there's no such thing as a cheap tire these days unless $100 each is cheap to you.

215x85 R16 is the correct modern size for 16"x4.5" rims.

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)