Cristal Clear Policy. Every product:
a) has personally been reviewed by me;
b) comes with 60 days no question asked money back guarantee (PayPal transaction-ID required);
c) has been scanned against viruses;
d) has been checked to see whether it delivers what's promised and to avoid poor contents
In depth review of PayPal. Except the programming details, this 40 pages PDF ebook includes every aspect about dealing with the most popular payment processor in the world. Very informative. Comes together with the reseller's site.