Keep in mind this study was only done for "rolling scars." The needling side went from 7.5/10 -> 4.9/10 while the prp + needling side went from 7.5 -> 4. Not a huge difference IMO, especially considering this was measured via photographs and not via depth tests. I think the extra difference could also be attributed to subscision with the prp needle - which has been known to help rolling scars in general.

Personally, I would save the money for extra treatments of something that works and not adding prp into it. I also think subscision > needling for actual rolling scars.

Here's another study:

http://www.ncbi.nlm.nih.gov/pubmed/21635618

Again the improvement is fairly minor (2.7/5 vs 2.3/5) but it helped quite a bit in the recovery process.