back in my early model building days, early 90'so, squadron mail order was the "***"! Sure, you had to mail your order form from the paper flyer found in finescale modeller, or the fuller catalog version if you've ordered previously, along with a check payment, and then wait "4-6 weeks for delivery", but back then, the anticipation was half the fun!
But, nowadays, I don't even bother! I look through the monthly mailer, then trash it, and if/when I need something, or have a project in mind, I go to Amazon first (yeehaw Prime!) And megahobby.com second. Megahobby.com has, so far, been almost as good as amazon. I am in southeast Pa, and they are based in Jersey, and their shipping is a prime-like two day for me, and their prices don't seem that bad either.
I kinda miss those days where you could get 4 1/72 scale A-4 Skyhawks on a high schooler's budget of around 10 bucks!