The pay-later craze is making everyone want to buy now. PayPal jumped on the bandwagon on Tuesday with an agreed $2.7 billion acquisition of Japan's Paidy, just a month after Jack Dorsey's Square struck read more a $29 billion deal for Afterpay. Rival Affirm's shares have jumped 41% since that transaction was announced, pushing its valuation past $24 billion.

In some ways, the frenzy is understandable. Installments are one of the few growth areas in payments, with the use of credit cards, debit cards, cash and bank transfers expected to lose market share in the coming years, according to a recent presentation by boutique investment bank FT Partners.

For $345 billion PayPal, which already has its own successful buy-now-pay-later service, Paidy brings another 6 million users. It's shelling out a similar amount per dollar of gross merchandise value as Square is for Afterpay. The figure is also a discount to where Affirm trades on that basis, making it an increasingly pricier target to buy now.