This is a basic exploit that i always use to save 1-2 silver per waypoint. Granted it does take maybe 15-20 seconds longer but i feel it's worth it.
There's 2 free hearth areas: Lion's Arch(Middle of the world), Hall of Monuments (North East of the world).
-To get free hearth to Lion's Arch
---Press "H" and go to Heart of the Mist, from there, you take the purple portal to Lion's Arch
-To get free hearth to Hall of Monuments
---You will need an item called Hall of Monuments Portal Stone. To get this item you go to Lion's Arch, go to Hooligan's Route in the north west of Lion's arch. There's a Karma vendor that sells this portal stone for free. Instant cast time port to Hall of monuments which is North East of the world map.
Depending on where you are wanting to teleport would you choose either Lion's Arch or Hall of monuments to get closer to your location. If you're already closer to the area you are wanting to teleport at then don't bother with this.
So let's say you're located at Lion's arch and you're wanting to travel to Fireheart Rise. To travel there from Lion's Arch would cost 3-4 silver. If you use your handy dandy Hall of Monuments Portal Stone. You'll teleport to the North East world map in which you're closer. Now taking the waypoint is only 1-2 silver.