I use the 16 round magazines with the base plate that makes them looks liked a flush fit magazine. Those base plates are about $8 + $20 or $21 for the 16 round Mecgar magazine (Greg Cote, LLC) gets you to about $28 per magazine.
I've also bought the 19 round magazines for about $30 each, again, Mecgars from Greg Cote, LLC and Midway USA (catch them on sale).
I've bought the +2 extensions from CZ USA and added them to 16 round magazines. They stick out a little, but who cares. Oh, the ones I bought were the +2's for the P07 and P09 magazines but they've been working fine on my CZ 75 16 round magazines for a couple years or more.
When I got them from CZ USA they were selling for $5 for two of them. Had to buy several (or was it more than several??)
You don't have to buy CZ stamped/brand magazines. Everyone says Mecgar makes them for CZ anyway, so just buy Mecgar and save yourself about $10 per magazine.