I'm not being funny, but if you don't know what you need should you really be atempting to service it yourself?
A lot of it depends on which service interval you are at. You could need all/some of the following: -
Oil
Oil filter
Air filter
Fuel filter
Spark plugs
Pollen filter
Cambelt + tensioners
Aux belt
Water pump
As for price, again it depends what you need to change. It could range from £40 (just oil and filters) through to £400.