The speed limits in the Czech Republic are 50 km/h (50 mph) in built up areas, 90 km/h (56 mph) outside built up areas, and 130 km/h (86 mph) on motorways.
The motorways are are just numbered and although they are toll roads they are free for motorbikes, the main non-motorway roads are also just numbered, and the smaller main roads just have road names.
The motorways signs are in Green, the main road signs are in Blue, and signs for the smaller roads are white.
The smaller roads are generally in much poorer states of repair than in other European countries, however the others are generally good.
I never saw any speed cameras and patrolling police cars I only saw on the motorways once or twice during my time in the country.
The Czech Republic does not use the Euro but petrol was generally cheaper than Germany and at the time of writing was the equivalent of 1.30 Euros per litre.
My favourite roads in the Czech Republic are those to the South of the country near to the Hungarian border.
To buy a SIM card for a mobile phone all you need to is to go in to any small shop that sells prepaid SIM cards. These shops are mostly small grocery shops and they are everywhere. No ID is required and when I did this the cost was around 5 Euros for one month of internet.