Pocket
I have good news and bad news. The good news is that you can get a really big improvement in your neck/decollete area (mine was wrinkly/crepey due to sun damage). The bad news is that the most effective treatment is Restalyne Vital, which means you get a doctor to put a lot of tiny injections into the skin. They have to do this at least three times (I had it done 5 times last year). The further bad news is that it needs to be topped up - I'll get it done twice more this year, I think as a maintenance. Further bad news is that I paid £250 per treatment. So that was £1,250 last year and another £500 this year.
If I'd started with one or two treatments 5 years ago, when the creasing first started, it wouldn't have needed such a big hit last year. I wish I'd gotten onto it early, really.
Is it worth it to me? Hell yes. Totally. But my skin was really awful and creased; someone who's had less sun exposure wouldn't need the same number of treatments.
The good news is, apart from working extremely well, you're banking the improvement for the future - it does almost stop the clock on the neck/decollete area.
If you can't stand the idea of needles or expense, you can try the Obaji Nu-Derm system too, that's about £100. I've got it but I'm too lazy to use it most of the time, and it gives subtle, slow improvement rather than the 'wooo, fixed!' effect of the Vital (which the doctor pronounced as Vitt-Tahl BTW, not Vy-t'le).