OK, I'm biting, or catching her plastic lemon grenade.
Icing sugar - yep, that tip works. It's been doing the rounds for ages. However, you need to own a blender. And the only way it truly saves you money (rather than a few pennies) is if you bake regularly. Home baking is tasty, but it's one of those things where it often is much cheaper to buy ready made from a shop. You could never bake biscuits from scratch for 39p for a whole packet. Or bake a ginger cake for £1. If it's all about budgeting, the best advice would be to buy baked goods.
Flour - different flours have different gluten and protein contents. Putting them into a blender doesn't magically change that. Yes, you can make bread with plain flour, but the texture and crumb will be different. You'd also need to adjust the wet ingredients.
Vegetable oil in salad dressings - hardly a novel concept. There are tons of recipes out there. I've yet to come across any Asian salad using olivr oil, for example. Same goes for most central European salads. However, due to global events, we are currently experiencing a massive shortage of vegetable oil. Our literal food expert seems to not have noticed though. May I suggest a lard-based dressing? #maverick