Need a car that gets good gas mileage, has German build quality, classic RWD handling, even a little cache, and is cheap to aquire? The BMW 3 series from 1975-1983 just might meet all your needs.
The BMW e21 (internal chassis code and identification to enthusiasts for this generation) was the successor to the very popular BMW 2002.
The top of the line six cylinder models featured a variant of the legendary BMW M20 motor. In 323i guise it made 143hp.

Unfortunately for the U.S. market, BMW only imported the 4 cylinder 320i model. To make matters worse, the motor in the 320i was strangled by emissions controls and added weight to in the form of U.S. crash compliant bumpers that looked very out of place on an otherwise handsome car.
However, there are some 323i models in the U.S. that were imported via the gray market. But the asking prices on these classic BMW cars can make the 320i look very attractive at a fraction of the price.
Many older used BMW cars often require cooling system attention, so when considering a used BMW, be sure to ask about what's been replaced and have a cooling system pressure test performed.
BMW's of this vintage are also known to have a front end shimmy if the bushings have never been replaced. Luckily you can buy the control arms complete for reasonable amounts and upgrade the polyeurethane to correct the problem for good.
Perfectly acceptable BMW e21 3 Series trade hands for around $4k dollars these days, but expect to pay a couple thousand more for a really nice one, and a couple thousand less for an example that needs immediate attention.
But with over 1.3 million cars produced, you can either wait for a nice one, or utilize the aftermarket and salvage yard to build a nice one of your own.