A fleece jacket or something similar plus a basic rain overcoat and rain pants can be had for not very much, even discount supermarkets will usually have something on sale.
Similarly a backpack doesn't have to be fancy, I know people who go camping with old laptop backpacks (preferable the beefy ones that can fit a 15.6" mobile workstation) or similar not very outdoorsy gear. Of course something along the lines of a $450 Savotta Patrol Pack would be superior in every way, but that's nice to have, not need to have.
Perfectly adequate tents, sleeping bags and mats are widely available for not a lot of money. Will they eventually break, sooner than high-quality gear? That's almost for certain, but the point is to get out there and do something, not to have the fanciest possible gear.
The one area where I would prioritize getting something a little nicer would be boots. A good pair of boots will greatly increase your comfort levels and protect your feet and ankles from damage. Again, I know people who go camping in sneakers, but actual hiking boots will be infinitely superior in rain and mud.
I would highly recommend subscribing to Steve Wallis on Youtube. He's a very down-to-earth guy who goes camping just about everywhere, with just basic gear and a positive attitude.
https://www.youtube.com/c/thestevewallis/