what it should include? depends if its a very minor one, or a major one, and what bits need changing,
etc etc etc.....
price? hard to tell without knowing what the car needs and if your going to some dodgy backstreet garage, one of your mates, or a dealer,
The 2001 1.2 is an ecotec, and has a timing chain, not a belt.
Check your owners handbook, the service schedule is in there.
Vauxhall wanted £200 or so to
engine oil &filter
The service kit including oil was £23 trade IIRR!
On my first service they also counted the wheels, and checked the brakes without removing the wheels (or if they do, they carefully dirty and age the wheels so you can't tell) They are supposed to check the lights, wipers locks and grease the hinges. (And they look for corrosion so you keep the anti-perforation warranty)
They also perform any safety recall work without publicity, and may upload software to the ecu so it stands more chance of running correctly. This is the only downside I can see to home servicing.
Otherwise at least I know it has been done properly if I do it myself, and it is hardly rocket science.
Hold in the mileage reset when you turn on the ignition until the display obviously changes, then let go.
Instant 12 month service!
I change the pollen and oil filter every year, the air cleaner every two years, and never mess with the spark plugs, but I only do about 4000 a year. I'd rather ride my bike than be stuck in a metal box, but somedays I have to use it.