>>2841264Burger here, but you don't have to spend much at all. Solo tents that will last a few trips are 20-30 and you can buy equally cheap bags, and sleeping equipment which will more than get you through. Esbit stoves and tabs are also dirt cheap and compact for heating water/food. 
I spent under 100 usd for the essential gear i needed
You can always err on the side of too little gear if you'll only be out for 1-2 nights. Worst case scenario is you're a bit uncomfortable or have to go home a night early.