there are literally tens of companies only in Prague providing these services... it has to go through the notary anyways and I don't think you will have any problems - just check the company history and request documents confirming it's not in debt and ask for the tax returns and published balance sheet and p&l reports
LLC company (s.r.o.) with no history and nonVAT payer should be around 500eur through ready-made provider (about 250eur if you form︀ a fresh one yourself)
monthly or quarterly VAT payer will be (way) more expensive, same︁ if you want a company with history or a.s. (stock corporation)