Heroscape is actualy the game I play, its how I found these boards looking for information to convert Mega Bloks ships for Heroscape.
Few things I wanted to respond too,
The main site for Heroscape players is the fan site, Heroscapers.com you can find all sorts of things there, from custom terrain, custom figures and tons of maps.
If your looking for Master set figures, like the Marro, Vikings, Matrix looking agents, WWII soldiers they are dirt cheap, even more if you dont want the official base. ( I actualy have a ton of spares if any one is looking for any of these units let me know, at the very least I can point you to some one who is selling for dirt cheap)
One of the biggest places we go to find our figures is here;
http://auggiesgamesonline.3dcartstores.com/Auggie ( Adrew) has great customer support, very friendly and ships international. Local to the US is a flat $3.50 shipping. Its the cheapest place to buy terrain right now.
Best place to score good deals online for heroscape in the US is craigslist, heroscapers.com and boardgamegeeks.com
Prices are starting to drop on rare squads on ebay too. Pricey units like the greeks, Gladiatron robots, Elf archers and dwarves usted to go for $40 each now they are going for around $20. Terrain is going up though. Most expensive terrain is Ice, although Jungle and lava are still kind of pricey. The trees are always hunted down by heroscape players as you can never have enough.
The names of these terrain packs are
Thaelenk Tundra - Ice tiles and glaciers
Volcarren Wasteland - Lava tiles - Toys R US Exclusive
Ticalla Jungle - Jungle trees and bushes
Road to the Forgotten Forest - 5 trees, road tiles and a bridge
There is also a small castle set, goes for pretty cheap,
Fortress of the Archkyrie
A lot of people said the same thing as you guys, that the secondary market is insane for some of this stuff, a $20 Aquilas Alliance monsterpack from 2007 keeps selling on ebay for close to $200 frequently. One of the main reasons most think hasbro dropped heroscape was because they wanted to concentrate on their core games ( thats what they told us ) Like Magic the gathering , plus they felt it was too much plastic for the price ( thats what we assumed)
Also they recently started using the heroscape interlocking tile system ( which they have patented) to display Avengers figures.
A bunch of us have tried to make copies of these tiles but they never seem to fit right, its easier to buy the cheap castle tiles from Auggies and flock or paint those. ( About .33 cents each)
I am sure there is more but I really should get back to work, any questions about heroscape I would be happy to answer as its my favorite game.