Leaking oil Ford Freestar-was halfway between two lines on dipstick when I checked last week-puddle this evening and am down just past the bottom line-put in a quart but am worried to drive the car to

If it's leaking from inside the engine then it would be coming from the valve cover. The cover gasket seal is no longer sealing properly. If oil is leaking down under the car then check around the oil pan, could be gasket or rear main oil seal or front oil seal.

clean the crankcase breather .

An oil leak will not affect the performance unless you do not have enough oil .Solution find the oil leak and repair it.

Cheap or Free ---I suggest you get rid of it
because the transaxle is about to fail ,as they
do on all those freestar & their predecessor

You might check the pulleys that the serpentine belt runs on. Make sure all are free wheeling and not loose or rough or make noise. You would need to remove the belt to check them.

The dipstick tube should be as high as the top of the engine, and you should be able to remove the dipstick from it by simply pulling it straight out (no unscrewing).
No oil should come out because engine oil only goes up about a third 1/5th the way inside the engine. So unless it is overfilled, you shouldn't worry about pulling the stick up and out.
Check the oil level with the car on level ground, and with it turned off for at least 10 minutes so all the extra oil drips down to the bottom of the engine first. Then pull the stick straight up and out, wipe all the oil off of it using a paper towel or clean tissue, then put the dipstick back in (you may need to turn it left or right just a little bit to help it past some of the bends in the tube). Push it ALL the way in, then pull it straight back out again. Look for the oil sticking to it at the bottom. You should see a clear line somewhere between the full and fill lines.
If it is low, but there is at least SOME oil, take it to a Jiffy Lube and have them check and top it off. IF there is NO oil on the stick, you should not start it until some oil is added.
I cannot go in to how to add oil here as it is different on different cars - but you do NOT put oil into the dipstick hole.

Personally, I would pour water in, it is a lot cheaper and if there is no leaks then you could drain it out and put coolant in.

BUT before you start it check your oil dipstick and make sure that you don't have coolant on your oil dipstick.

It's under warranty, have them fix it and document everything in case you have to file a lemon law claim. PS: Report dealer personnel to general mgr, that's not customer service.

It is either being burned off in the combustion chamber or leaking into the oil pan.
Check your oil level on the dipstick and note any abnormalities; way overfilled, foamy, tan colored, etc.

If nothing, have the cooling system pressure tested.

Note that GM issued a recall on these vehicles for intake manifold coolant leaks, resulting in your situation exactly. Verify the recall has been performed.

then u have a leaking cylinder head gasket.