Is this LS a V6 or V8? I suspect from the asking price that it is probably the V6.
Yeah, repairs can get pricey in a hurry, especially if you don't do the work yourself. However, like most other cars, if it is maintained well and treated kindly, it can be a very reliable car. Or, you could get a lemon and have all sorts of problems with it. There are owners with both types of "luck" that have posted to this forum in the past.
My wife has a 2002 with the V6. She's had virtually no problems. The ones that she did have were promptly fixed by the local dealer and covered under warranty. I had a 2004 V8 and didn't have many problems, but the one I did have (a vibration) was a royal pain, so much so that after only 1 year of ownership and 6 trips to the dealer for the same issue, I traded it for a different car and ate the $6k loss from purchase price to trade-in value. I have to believe I got one of those lemons. Lincoln even flew a field service engineer out to ride with me and experience the concern. He acknowledged the concern, but even his attempts to repair it were not successful. I must give Lincoln credit, they do seem to have pretty impressive customer service.
For the price, the comfort, power, and "fun to drive" factor is difficult to beat. Even though I gave up on my LS, my wife and I still enjoy hers and I do not feel the need to bad mouth the entire product line. I think I just had bad luck with mine.
-Rod