I'd say that the majority of the tasks you can complete are free, however there are some that involve getting money back following a purchase or after using your credit card to enroll in a free trial somewhere. Here's an example of a paid trial offer I completed: I signed up to a free trial of Blockbuster (similar to Netflix where they send you DVDs in the mail) and I received $11 for it. I canceled the subscription right before the free 30-day trial was over.
There are numerous tasks that are smaller and pay less - for example, I signed up for a free sample of liquid fabric softener and received 50 cents. Everything adds up. I use an e-mail address for doing these offers that's not my primary e-mail address. Essentially, you're giving away your contact information for cash with these offers, so you can expect you'll get a lot of e-mail advertisements.
I love DSFC, since you can earn money by performing these various tasks even while watching television.
The Real Money is in Referring Other People
You can do surveys and offers until you're blue in the face, but there is a limit to how many you can do in a short time period. There are people who do make $100-200 each month just by performing the various tasks available.
The serious money is with referrals, however. Their referral program is very good. Once you start out (and have no referrals), you earn 20% of what people you refer make (1st tier), and you also make 10% of anything their referrals earn (2nd tier). As you work your way up, these percentages gradually rise to 30% (1st tier) and 20% (2nd tier).
Obviously, the individuals you refer must use it. If you just refer a bunch of people you know and they create accounts but don't do any surveys or offers, you're not really going to make much money from them.
After your account balance gets to $20, they send you a check the following month. After at least one check payment has been deposited, you'll have the option to switch to being paid via PayPal.
This site isn't going to make you rich, but this is another great tool to add to your own collection of online income sources.
If you have a blog, website or social media account which has anything to do with earning money, saving money, or personal finance, it might be worth introducing it to your readers as a way to pick up some referrals.