Depends on what’s leaking.
If it’s the drain plug, it’ll be cheap. Especially if it’s a nylon washer that needs replacing. If they tell you a new oil pan is needed GO ELSEWHERE!!! This seems to be the latest way of stealing money. Even a stripped bung hole can be cheaply repaired.
If the seepage is around the oil pan and they tell you you need a new pan gasket GO ELSEWHERE!!! Oil seeps past oilpan and valve cover gaskets due to pressure in the crankcase not being properly relieved by being drawn into the induction system, often due to a plugged PCV valve. Granted, the gaskets get tired, but replacing an oil pan gasket can require a lot of disassembly underneath the vehicle, and it can get expensive. Not worth doing IMHO.
If it’s seepage around the valve cover gasket(s) (what kind of car is this again?) it might be as simple as a new PCV valves and new valve cover gaskets, modestly priced.
If it’s from the main and/or cam seals, and it’s a timing belt engine, expect the cost to be in the hundreds… 'cause the water pump SHOULD be replaced along with the timing belt and tensioner when the crank seals is changed. And oil can cause a timing belt to fail prematurely, so if it’s a seal it should be repaired.
Also, monitor your oil level. No engine ever got damaged due to an oil leak unless the level was allowed to drop below the oil pump’s pickup tube. As long as the pump has an oil supply, the internals will be properly lubricated.
Of course, if you have a Ferrari, ignore everything I’ve said and get ready to mortgage your house…
So, again, what kind of car do you have and how many miles are on it?