Amazon has just added another offering in its attempt to conquer all business: Local Register, a credit and debit card processing for small companies. That puts it into direct competition with the likes of Square, Intuit and PayPal, all of which offer card reader and app combinations that turn smartphones into payment processors.

As the company often does, it has undercut prices of its competitors, at least on a temporary basis. Companies that sign up by October 31 of this year get a guaranteed swipe rate of 1.75 percent through the end of 2015. That compares to 2.75 percent for Square and 2.7 percent for PayPal. Manually keyed transactions see a fee of 2.75 percent rather than 3.5 percent plus a per-transaction fee of $0.15.

According to the pricing fine print, rates will rise to 2.5 percent for swiped transactions and 2.75 percent for keyed ones come January 1, 2016.

Funds are available the following business day, which means that Amazon's payout will be as fast as anyone's in this industry. Money is available to spend on "within minutes," much as PayPal does. Amazon also touts live customer support and analytic reports built into the app.

The reader isn't free as is the case with Square. Instead, like PayPal, Amazon charges ($10 including two-day shipping) and then provides a credit in processing fees. There are also cases, stands, receipt printers, and cash drawers available, though no credits promised against their prices.

Adding a card reader and service to its offerings is a logical extension of Amazon's attempt to get e-commerce sites to use it for payment processing.

As the well-publicized fights between Amazon and major publishers like Hachette have shown, the retailer and service provider is comfortable using its weight to try and force deals that it wants. The company's aggressive plans have hurt its earnings, and there may be pressure from major investors to shore up the spend-to-get-markets approach that CEO Jeff Bezos has freely used for years.

In addition, Amazon will have mountains of additional purchase and pricing data handed to it. Although that hasn't necessarily been a problem with the likes of Square, PayPal, or Intuit, the company remains a predatory retailer. Small companies might find themselves giving away information that eventually allows Amazon to compete with them as well.

It might be wise for entrepreneurs who find Amazon's offer attractive to also maintain other options, just in case.