1996 Honda Civic spark plug

It all depends if they can remove the spark plug with the cylinder head still on the car. Most times on these vehicles they cannot since the spark plug tube is quite long and it's hard to access the spark plug from the top.

To remove the cylinder head you are looking at over 6 hours labour, plus a gasket set (head gasket, exhaust, intake manifold as well.) Possibly a timing belt as well if necessary.

Unforunately it is not a cheap job.