I check ebay as well, as almost all of my Corgi trucks and WWII vehicles were purchased on ebay. Check the price and selection of both the diecast speciality shops and ebay and buy whatever you like.
Local hobby shops (even if not train shops) will often have a nice selection of model kits available, although the prices are sometime higher. I also check the local toy store (Toys r Us or Walmart) when I'm shopping there. Likewise with Ollies's (a PA/MD surplus store), as you never know what you will find.
My problem, is that I have found way to many sources of loads!
Jim