Don't discount looking at used items from somewhere like Facebook marketplace or forums such as this one. I managed to snag a nearly new sleeping bag (only ever tried out in the living room) that retails for £450 new for £150. It's in perfect condition, weighs 800g, and is rated to -5°C. I've been too warm in it.
Same for tents lightweight cook sets, etc. If you're patient and keep your eyes out, real bargains can be had.