dont have my own money to secret shop with

While that limits the kinds of shops you do, it doesn't eliminate entirely your ability to shop. There are some shops, such as bank shops, that require you submit a business card along with your report to prove you were in the right place, but have no purchase requirement. There are some shops where you are visiting a store to see if a particular product demonstration is occurring at a particular time that have no purchase requirement. By far, however, the majority of shops require a purchase of $1-5 for which you will be reimbursed in 4-8 weeks.