In order for me to to the PayPal Pay in 4 does the retailer have to specify that on the site like other companies that let you buy now pay later, or as long as they have PayPal as a payment option one can do it. I have done one purchase as such, but for the life of me I can't remember how I got to where I was able to check out that way. I must note I don't have the PP app downloaded, and generally shop on my computer.