But I tried to make do with what I have already
Layers should be the answer as warm air is trapped between each layer. The base layer should take moisture away from your skin, so no cotton. The mid layer is the important one to provide insulation, micro-fleeces, merino wool tops, breathable fleece or thin insulated jackets, and an outer layer to protect you from the wind and rain - waterproof and breathable if possible. Using a layering system will allow you to self regulate your own body temperature as you feel necessary.
I live in Scotland so, yes, I do need it more than others here but I don't spend a lot of money. I find if my extremities are warm I'm OK - feet. hands and ears. I often go out walking and need to remove my gloves and hat because I'm too hot.