Do the math. Derma roller
Do the math. Derma roller cost $10-20 and can be used only 2-3 times without the needles being messed up. They don't give an even penetration either. With the pen you save money in the long run and get an even penetration that you can't get with the derma roller. Pen over all is very high quality and the battery lasts for a long time. Maybe I have to charge it every 2-3 months.