Subcision would be needed if there is tethering. Filler will give temporary relief - you will have to repeat every 18 months almost. ... cost of filler depends on amount of filler.. which depends on the SIZE of that the scar. Also, as a cheaper alternative you could do subdermal fat grafting with PRP fibrin gel for the scar- but this would be less volumizing than a filler. Instead, you could consider doing CO2 laser or Er:Yag laser sessions ; 5-6 sittings to improve the skin texture (upto 60-70% ) over the scar and the result from this will be PERMANENT. However examination of the scar would be needed to decide if you would benefit with it & if filler is to be used - which one to use- whether volume or juvederm XC or juvederm Ultra. You should send me images through private online consult for a better assessment of the problem and approaching it accordingly. Hope this is helpful.