What is a 1944 copper penny worth with the liberty spelled with a lower case L?

What you most likely have is a grease-filled die error (or just simple wear). In a grease-filled die error (sometimes called struck through grease) too much grease was added to the die and so the leg of the "L" wasn't struck fully making it appear as "l" these errors are very common and bring little additional premium.

Your coin is worth about 3-10 cents if circulated or about $1 if uncirculated. Its a common year.