Locals
If you are local, just take Metro (Underground) line B (yellow) and get off at Karlovo namesti station.
Slovakia
There are many regular buses going from Slovakia to Czech Republic. You might also want to use EC train, check international timetables here.
Hungary
There is an EC train going from Budapest to Prague. Check international timetables here (Switch to english in right bottom corner).
You can also use Orange Ways bus line, orangeways.com.
Check Wizz Air for low cost flights to Prague.
Germany & Austria
Again, there is an EC train going from Berlin/Vienna to Prague. Check international timetables here (Switch to english in right bottom corner).
Other countries
Several lowcost airlines operate at Prague Ruzyne airport, airport code is PRG. Namely:
Wizz Air, EasyJet, SmartWings and many others.
We recommend checking airlines above first, then check Expedia, Kayak, whatever you want.
Accommodation
There are several hotels in the area, including cheap hostels. Check yourself:
