Ebay was another option too.... That's where I got mine, fairly cheap. And brand new. Just remember fitting sizes, make sure since you already ordered the heater, to get a filter with the same size hose. Also, the difference between the 200 and 201 is fitting size. The 300 only comes in 1 fitting size. I have it on my XP3, and works great. Same size, so no need to try to adapt it.
55G Filstar XP3 - 16" Fire Eel
75G Medium Planted - Filstar XP3 Low Light - Established Feb 2006