If you're not too concerned with cosmetic appearances, I've seen surplused CZ 75s (pre B) at and below the $300 price mark on both CDISales (gunbroker) and Bud's firearms. Not sure if they have sold out of their run yet.
For those with concerns- yes, the guns in question are marked at "Fair" or below condition cosmetically. But keep this in mind:
the guns in question are steel framed. CZ would take the steel frames/slides, parkerize them, then apply a spray finish ("polycoat" for 90's and forward, enamel for the 80's vintage). I have 2: an 89, and a 92. The 92 has a better, polycoat finish, and there is wear on the rear gripstrap. The 89 has a couple of areas where the enamel paint has chipped or worn off. It looks pretty "ugly", but it's clearly not white steel showing through- it's a light gray park that many owners confirm is tough as heck. No rust on either pistol.
Shipped condition: the 89 came recently from CDI, it quite honestly seemed like it was dunked in used motor oil, then buried in a sandy ash tray. It literally smelled like that. It had grit all up in the internals. That said, a very quick field strip with ballistol cleaning (slide rails and barrel only, basically), it was stunningly accurate with a good, light and smooth trigger in both DA and SA. I hosed it out liberally with a can of break cleaner, changed the recoil spring, applied grease to the rails and ballistol everywhere else, and it now feels awesome. It still looks a little rough, but it shows character, as they say. Since it is steel framed, it CAN be sent to have any refinish applied, including a nice rebluing... and you'd still be ahead of the game pricewise.
Relevant parts, warranty, etc: not covered under CZ-USA warranty. MOST parts are interchangeable with CZ 75B's (check the czforums for the list). Springs are cheap and available at Wolff's.
Magazines: flush 15 mags are pretty rare and pricey; the current B mags are just the slightest bit too tight in the magwell. There are 2 major ways to overcome this;
for the adventurous, the cz forums have threads showing exactly where to file (very lightly), to open up the magwell. People have stated that it only takes a few strokes to get correct fit, and that the old mags still fit afterwards. If you're getting it refinished, this is a real option, then you are gtg with all mags afterwards.
If you are hesitant to file, I can 100% confirm that the 18+ rd mags for the SP-01 fit and function perfectly. They extend from the base about a half-inch, a lot like an 8 rd mag for a 1911. They look good, everything fits tight, and I haven't had any problems.
Grip availability- again, 100% compatible with B grips. I have bought the factory rubber grips and put them on both guns, and they feel fantastic. I also have a wood set for looks, but those are tucked away after I got the rubber.
Photos are of the 89, after unboxing it. Original grips and 1 original magazine. A WHOLE LOT of gun for $300.