Expensive option:
taxi ... expect to pay over 100* USD if the driver is not too creative, but do not worry s/he has no real need to be so, due to incredible legal high fares.

Not too expensive:
MXP-city center by train Malpensa Express
city center-hotel by taxi, it's in the range of 25-40 USD depending on the traffic jam and on the route and... well I do not like Italian taxi driver at all !

Even less expensive but tricky:
rent a car, drive to the hotel, drop off, check in and give it back to a rental office in town. MXP is considered Milan, so no drop off fee if you give the car back in a city office. Could it be feasible if it's not your first time in the city and you are not too tired.

* if you go all the way by taxi and the highway it's jammed, (it happens) do not worry for the poor taxi driver, s/he will be a real happy bunny... the legal fare is based on distance, time of the day and travel time... if stopped for e.g. 40 minutes you are charged for that idle time, the maximum MXP-city center fare I hear of was in the range of 300 USD. The English verbal capabilities of a normal taxi driver are... well, Italian.

Only a very few taxi driver accept credit card so you simply need cash, a lot of Euro.