They CAN work depending on what you're selling. Affiliate leads are usually low-quality and sometimes fraudulent.
A few steps you should take
1) Limit the amount you're willing to spend over the first few days. Like any marketing platform you need to figure out if this is one that will a good return on investment.
2) I would try to set it up so that you only pay out on a successful sale. While not required, it probably makes the most sense for digital goods
3) Check out the other ads on the affiliate marketer.
