I have an interesting variety of scars of various sizes and depths. A while ago I used some scar-reduction gel patches that were like a piece of tacky plastic sheet, that you could wash and reuse, and they would stick to the skin. After a few months they did make scars smoother. However you have to wear them about 24 hours a day for three months, and some of them won't stick as they rub off on clothes or fall off with movement. On a limb you can use tubigrip or something, but I also have scars on my back, for example.
I've had another look in the pharmacists recently, there are some creams, and some use-once dressings. However using several a day for several months will cost a fortune (they're not cheap)
Any other ideas?