I have a Fuji XT2 and wanted to get another lens, 56mm f/1.2. Online prices are 899.99, i. E. $900. Greentoe says save 10% to 40% in their advertising. The best counter offer to my $851 was $879, an about 2.5% savings, plus the hassle of multiple rounds of bidding.
Bottom line, If you know what you want, and it something that does get discounted, you might get a deal (seems like TV sets fall into this category) but Fuji lens are not in this category.