The actual cost to replace ignition coils depends on the vehicle and how many ignition coils the vehicles have.
If your vehicle has 6 coils then it would cost less than a vehicle with 8 ignition coils.
Ignition coils cost from $30.00 to $40.00 each depending on vehicle so if you need 6 ignition coils then you'd be looking at a cost of $180.00 to $320.00 just for the ignition coils.
Then if you have a shop do the job to replace the ignition coils it will cost around $100.00 to $300.00 for the labor depending on how hard it is to change out your ignition coils.
If you look online or ebay you can sometimes get ignition coils for your vehicle for as low as $10.00 to $20.00 each and if you can do a little work and studying it's pretty easy to change out the ignition coils.
Sometimes the ignition coils are attached to the spark plugs in newer vehicles as well so it's not that hard to change them out.