That's because you don't know where to park. There's a
free-on-sunday multi-storey carpark which is just 5 mins to
Serangoon station, of which you take another 5 mins to walk from
the station to Nex. It's about the same amount of time to walk if
you park at the far end of the carpark that is being charged. I
have walked the route before, and it is very near.
The same thing applies for Hougang Festival Market. The most
obvious HDB carparks have no free Sunday Parking. There are less
obvious hidden ones which are of the same walking distance if you
know how to cut across HDBs, but still free.
If you wish, I can point out to you on a map when I get home
tonight to my PC where the free-on-Sunday HDB carpark is that is
near to Nex.
Please keep all these free stuff to yourself, otherwise, next
time, I got no free place to park anymore. Thanks