How to fix my transmission leak for cheap? Help?!

My 2004 Ford Taurus Ses has a small leak and right under the transmission tube opening where the dipstick goes there's a puddle of transmission fluid right under the opening of the tube and there's black substance all around that area and my dipstick seems to come off easy it doesn't have a tight grip on the tube should I put transmission fluid with blue devil in my transmission to stop the leak a mechanic told me I need a new dipstick and another mechanic told me I have a small leak and I can still drive it so and all over the trans tube there's wet/dry black substance on the trans tube running down from the top to the bottom of the tube and I used a t-shirt to clean it and it came off with little to no effort Experienced advice would be helpful and especially with my specific car would be helpful Thanks! Help

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