How do you find older figures w/o buying from scalpers?

Ever since Sonic started really taking off in the latter part of last year Jakks figures and the good merch in general is just harder to get ahold of now. When I first started Ebay and Mercari were a bit of an upcharge but nothing outrageous but we all know how that's going and store shelves are basically barren.

I know part of it is just straight up luck, but where are some places you go or methods you use to find older/rarer figures like super silver, chaos, neo metal, metal virus sonic, etc?