Could invisalign help my tmj? Or could it be worsen? How much does it usually cost?

Yes. Tmj (temporomandibular joint) is more accurately referred to tmd (temporomandibular dysfunction) is an enigma. It takes the two most complex joints in the body and attach them together with a bone (mandible). Invisalign could make it worse or better, but doing nothing could also make it worse or better no one knows. Straighter teeth may have a better chance at supporting your joint. $5500.
Doubtful. Orthodontics is not considered a cause or cure for TMJ issues - even invisalign. There is always the possibility that plastic aligners between teeth may help TMJ symptoms, but there is absolutely no guarantee. In other words, do not seek invisalign with unrealistic expectations. Professional fees are best discussed in an examination with a licensed orthodontic specialist.
Possibly. It would depend on why you have problems with your tmj. If misaligned teeth have affected the way you bite, then that could cause TMJ problems. It is not too likely that it would get worse, but there is no guarantee that it would solve your TMJ problems. Invisalign usually costs as much, if not more than 'regular' bracket and wire braces. Plan on $4000 -$5000 for a full case.
You need treatment. You need joint treatment. Clear Aligners may help, but not as much as braces, if you have a malocclusion. Don't decide on treatment based on a gadget, base treatment on what will best treat the cause of your dysfunction. Every Dentist thinks they are an Invisalign Expert. You need a TMJ expert instead. Find a qualified Orthodontist for the best result, no matter the gadget.
TMJ and Ortho. First, any tmd\tmjoint symptoms should be evaluated by someone with extensive training ; experience in this area. Very few dentists really understand this complex issue. Secondly, any occlusal (bite\jaw discrepancies should be evaluated by a qualified orthodontist. Then the two dentists should confer ; along with you, discuss how best to solve ; not create problems. May or may not be related.
No. Invisalign can only tip and rotate teeth. It cannot move the roots through the jaw bone very much. You really cannot achieve relief of TMJ symptoms unless significant bite changes are made to realign the joints - if that is in fact what is causing your symptoms. Best get a proper diagnosis regarding your symptoms to know what therapy will work best.
Unknown, however... I tend to shy away from invisalign for patients with TMJ issues. Invisalign doesn't allow the orthodontist as much control over the treatment as braces do. Tmj patients require exquisite fit of teeth to have a chance of being comfortable. Braces are capable of this(in capable hands), invisalign can struggle to get what we need for these patients. I hope you can find a comfortable solution.
May Make it worse. Invisalign braces can make your TMJ worse. The cost can very from about $3500 - 5500 and can take 6 - 18 months for treatment.. The literature says that TMJ syndrome or tmd may or may not be related to your tooth position. A conservative approach would be to have a bite plate or night guard made and then re-evaluate your symptoms. If no better then try physical therapy.
Depends. Tooth movement can exacerbate an underlying problem and bring about your TMJ symptoms. TMJ symptoms can improve with invisalign if the bite problem corrected is ontributing to the TMJ problem. Cost is extremely variable. Ask around.
YES and NO. Hard to say. You need a thorough history and examination to determine treatment. Phase one is helping the tmj/tmd symptoms, and the phase two may involve braces/invisalign. V costs vary from state to state.