The drivers meter was moving so fast you could hardly read the numbers flying by. In the end he wanted around $50 for a ride we took the day before for $7. We threw in about $10 worth of crown and got out of the cab. I don’t suggest doing this anymore. Stories fly around about self locking doors and electric handles (not sure if it’s true, but not worth trying). Advice- Anytime you can, have your hotel call a cab for you. If you can, grab a card from the company so you can use them again. Also Avoid cabs that look more like your uncle’s old Nova hatchback. Lot cheaper.
I took a taxi from Hlavni Nadrazi to Dejvice in a taxi that DID NOT have rates posted on the side. The meter had to running at the rate of about a crown per second. The ride cost me about 1200 CZK. The ride I took earlier from the Dejvice to Hlavni Nadrazi cost about 240. Negotiate price before you get into the taxi, AND make sure there are rates posted on the outside of the cab.