You can go a long ways toward decent outdoor kit by simply repurposing common household items - matches in a water tight pill box, a square of plastic sheeting, etc. for very little outlay.

There comes a time when the best strategy is to simply bite the bullet and pay for a really good item. Choose wisely and it will serve you well for years and years.

Serving as a draftee in the military many years ago, I swallowed hard and spent a month's pay for a really good down sleeping bag ($100, 3 lb weight, used it in well below zero conditions). the next month I blew half a month's income on a Kelty frame pack - state of the art at the time. These are 1960 prices...

These items were waiting for me at the end of my military service, and served superbly for several years. Both were eventually pilfered. I am sure the Kelty would still be in occasional use, if I still had it.

Overall, the items were worth subsisting on nothing but Army chow for a month. I think there are three things well worth spending bib bucks on - bag (sleeping), backpack, and boots - the three B's. The rest can be improvised - open camp fire, repurposed tin cans, plastic sheeting, etc.

If you get into technical climbing and rope work, it is time to spend money again - a good rope, well cared for, is super critical.