You join a "Get Paid To (GPT)" site/program, usually giving them your name, email and other demographic information, and the site/program owner delivers advertisers ads to your email box, and you click on the link in the emails to visit the advertisers' websites - yes, you are actually get  paid to view ads! Usually you get paid cash or "points" for reading and clicking. Most of those sites also offer other ways to get paid such as shop and sign up offers.  

Most of these "GetPaidTo" sites are short lived - for some reason, they don't "survive" for a long time, they come and go. It's not uncommon you heard people complaining they are scam! Also, majority of those sites pay really low, they usually pay less than one cent, which make them not worth your time!

Tip: if you do those low paying (1 cent or less per email) paid to read emails, make sure you cash out as soon as you reach payout - you never know when they are going to close their doors!

However, there are a few honest, reliable and "high paying" sites that actually worth joining in my opinion - Below are the BEST paying PTR sites, all pay 1 cent and up - most of them are cash paying site either by Paypal or check.

---

Hits4Pay - You receive $5 in your account when sign up as a member. They send you emails according to your interest. You earn $0.02 for viewing each ad. Cash out minimum is $25.00. Pay via Paypal. They also have a two-tier referral system. You need to login to your account to read the paid emails. Their paid emails/paid ads do expire so make sure check their emails at least once a week.

DealsnCash - They pay $5.00 for sign up, $0.01 - $0.02 for viewing each email/ad. They also have a double tier referral system. Minimum cash out requirement is $30, and they pay vis Paypal. (Please make sure your Email provider don't block DealsnCash. Their paid emails/paid ads also do expire so make sure check their emails at least once a week.

Note: Hits4Pay and DealsnCash have plenty ads if you select the right categories, please read comments below to find hint (my answer to paul).

MyPoints - You earn 5 points, which worth about $0.03 for reading an email, and cash out minimum is 1600 points ($10). They also send surveys that offer 10 - 50 points, you earn 10 points if disqualify. Points can be redeemed for Cash via Paypal, Amazon Gift certificates and other popular retail gift cards. I have cashed out quite a few Walmart gift certificates and they send the cards very quickly.

InboxDollars - You get $5 just for signing up at Inboxdollar.  They pay $0.02 for reading/clicking each email,/ad. You can also earn from taking surveys ($0.5 for daily surveys, and they do have target surveys that pay up to $10), completing paid offers, doing search and simple tasks etc.  They also have a referral system. You must earn at least $30.00 to request payment (via check).

SendEarning - You get $5.00 sign up bonus. SendingEarings is the sister site of Inboxdollars. It works pretty much the same as Inboxdollars. They pay $0.02 for reading each email/ad, and you can also make money by taking surveys (daily surveys and target surveys), completing paid offers and shoppings. Minimum payout is $30, and they pay via check.


Tip:
As you can see some of the sites above have a pretty high cash out requirement of $25 or $30. So finding active referrals will greatly shorten the time needed to reach the minimum payout, especially for hits4pay and deaslncash. Even it's just a couple of friends signing up as your referrals and actively clicking ads, will be very helpful.