I had standard metal braces as a kid, but never got a retainer. So my teeth are much better than the snaggle-toothed mess they were, but they've drifted. One tooth is so far out of alignment that it's damaging the tooth above it.
My dentist said I was a good candidate for Invisalign, since it was only those two teeth and a few cosmetic gaps. He quoted $5200, split into two easy payments!! I shopped around and found SmileDirect. $99 trial kit (which was on sale for $25 during Black Friday) to see if you're a good candidate. Or they can hook you up with a local dentist. I skipped that option, since my dentist had already cleared me, and I would continue seeing him for the duration...just not get the braces from him. It was $1850 for the total cost, and I paid for it with my FSA. (They contacted my insurance to see if they would be covered, but alas, no.)
I couldn't be happier with them--except to have never had braces in the first place :) You take pictures and send them in periodically to check your progress. They send me email & text alerts when it's time to put in a new set of aligners. They shipped me everything I needed in one box--all of my aligners, labeled by date I would use them; a removal tool; lip balm; and several tubes of whitener that I can use in conjunction with my aligners. About six weeks before your time is up, they email asking about a retainer. They're $99, replaced every six months.
All this to say, shop around. My mail order braces are doing the same job the expensive dentist-ordered ones, for less than half. At my last dental appointment, my dentist said they were working well.
You can talk to your insurance carrier, too, to see if they have recommendations.