won't be much money, in my experience there's a fine balance between reward and time invested that you have to feel out.

the methods that stuck with me over the years were

a crap extra phone with nielsen mobile (super spyware-y, hence the burner)

slidejoy and another lockscreen ad app on same burner

sometimes receiptpal is good if you purchase things in person a lot and get paper receipts

prolific.ac surveys and studies (those pay well enough for survey work and are legitimate)

google opinion rewards for free play credit (good for in app buys, paid apps you can't find a pirated apk for)

heard various things about places like fiverr and mturk, tl;dr your mileage may vary with those but some folks swear by them

Reddit's /r/beermoney turned me onto most of these, it goes to shit every few months though and quick/reliable/legitimate is often a "pick two" situation

best of luck, sorry for typos and/or formatting as am on mlbile atm