I bought my Olympus XA at a church sale for $3. I also found a nice Rollei XF 35 for $7.95 - these are vastly overpriced.
Last year, I bought six folding cameras for $300. All were in excellent condition, except one that needs its lens helicals relubed. The six are Super Isolette; Isolette III with an f/3.5 Solinar; Super Ikonta 531/2 (6x9) with a coated Zeisss-Opton Tessar; Certo 6 with a coated Jena Tessar; Balda Six and a Bessa I (6x9) with a coated Skopar.
More recently, from eBay: A Contax III with a working meter; Olympus 35 RC; and Agfa Optima Ia for $49. And then a clean working Rolleiflex SL35 body for $50.