Each company has its own policy regarding payment. I’ve been paid via PayPal, Visa/Mastercard/AMEX prepaid cards, and Amazon gift cards. When you first learn about the study, payout information is provided so there are no surprises. The one thing that varies greatly is when you’ll receive payment. When I participate in local studies, I receive payment immediately following the study. When the study is done online, I’ve been paid as soon as the next day. The longest I’ve waited for payment has been 30 days even though they’ll say it can take up to six weeks.