There's a new breed of apps that offers cash back and various reward when you link your credit card or bank account. An easy way to double on this income source is to refer friends. While that sort of scheme may sounds too good to be true, we've tested these to make sure no initial investment is required and that it's not anything dodgy behind. You're good to go!

Here's a mix of food delivery and meal kit services that offer great signup incentives, as well as generous bonuses when you invite friends. Have a bite!

It's annoying to switch website hosts, so companies are investing aggressively into referrals. If you are a developer, work in tech or related field, you might earn generous rewards by recommending hosting and domain names providers. DigitalOcean is especially easy to recommend as it's priced very aggressively. On top of the invite bonus, company making to switch are often able to slash their hosting cost in half. We recommend services with rewards or not, so it just make sense to claim our due. Who doesn't love free computing?

Here's our full list of travel apps and platforms that offers generous rewards. From the leaders like Airbnb and Booking Uber, to the big bonus offered by insurance companies like WorldNomad, you are sure yo find programs that fit you here.

Regular travelers might already use a number of these apps, so now is time to get your hands on your invite code and post it on this site!

Many of these apps also have great signup bonus.

There's now a wealth of banking services that offers generous rewards when you invite friends. In many case, these online banks are amongst the best service of in the banking industry so it'd definitely worth checking these out!

The gig economy is here to stay and help number of people supplement their income. Referring qualified new rideshare drivers or airbnb hosts have some of the biggest payouts. You are basically referring an employee which is invaluable for the platforms, and they'll reward you generously. For example, referring an Airbnb host will earn you 8 times the amount you'd make referring guests to the platform. If you're only promoting a few programs, these offer great rewards! These platforms can be lucrative if you have the time to give them a try!