[jacquesm]

Amsterdam pirate stations in the heyday of pirate radio (and TV!) had spares on the shelf. It usually wouldn't be more than an hour or two after a raid and they'd be back on the air as if nothing changed. In rare cases stations were off the air for more than that, and usually only because the studio itself had been raided and that took a lot more to put back together again than the transmitter location (usually far removed from the studio).

[dmix]

How much does a transmitter (station) cost?

[jacquesm]

Depending on the output power anything from a few hundred to many thousands, especially if you want it to be clean.