emission workshop message

My VW Passat 2000 just got a diagnosis after code reading: misfires on cylinders 3 and 5. Mechanic suggested to replace Platinum Sparks plugs, Plug wire Set (he said it was never replaced since 2000) and Ignition Coil. Do all these replaces have to be done at the same time? kind of expensive for me. How much can I ride while looking for another cheaper repair? Please, if someone can help me with this asap, will be very appreciated. Thanks.
solracamazon