Hi charmaine, welcome to Outdoorking.
Please tell us what kind of mower, with what kind of engine - a picture or two would help a lot. If it turns out to be a Briggs and Stratton engine (most of them are, but there are several other engine brands commonly used), we need the very long series of numbers stamped on its top cowl. We also need to know where the oil is coming out.
I'm sure once we know what engine it is and where it is leaking, we can tell you how to fix it. That doesn't mean it will necessarily be easy to fix, or that you will have the tools required, but let's get to the bottom of it so you can have the choice of whether to do it or not. I agree that the cost of having a repair shop fix an old mower is often not worth spending.
