My wife still builds with Lego from time to time. They are getting expensice though.

LeBlanc, I buy them in bulk lots from reputable eBay wholesalers by the pound - you’ll never know exactly what you’ll get, but that’s the fun challenge of working with LEGO. Also in Minneapolis at the LEGO Imagination Center, you can load up with specialty parts at a whatever you can fit in a cup price (like a one trip only salad bar).