Hi Stevej,
Yes I can confirm there is free parking at the top of Avinguida d'Encamp, however it can be very difficult to get a space there, particularly at the weekend, best time to try is later on at night or very early in the morning avoiding the day trippers coming up from France. The car park can also get very snowy / icy so take care where you park to ensure you don't get stuck. I'm sure you will manage to get a space eventually, but if not be careful if parking on the street as they are very quick to tow / clamp illegally parked cars in Pas!
Emma