The old Bessa, with the Voigtar lens, usually goes for $25-35. It sometimes comes with the original 6x6 mask. You can also get lucky sometimes and find one with the Skopar lens within your budget.

The 6x9 Ikontas with the Novar lens may also be available in that price range.

You'd have better luck with a camera that uses 620 film, as long as you're willing to respool. A Kodak Monitor with Anastigmat Special, or the Kodak Tourist with the Anaston lens are commonly available for $40 or less. Don't get the Tourist with the top-of-the-line Anastar, because the Synchro 800 shutter it's paired with can be unreliable. Neither of these will have a mask.

It's kind of funny that someone would push (yes, that's the correct word) someone toward a $500 kit when they clearly want something simple, with one adequate lens and the ability to make aperture setting changes.