Square has been working hard to expand its mobile payment solution at retail, and a new partnership with Verizon Wireless promises to make it available to even more iOS and Android users.

Verizon Wireless announced Thursday that all of its retail stores across the United States are now offering the Square Card Reader for sale.

The tiny plastic widget plugs into the headphone jack of any iOS or Android device and allows small businesses and independent contractors to accept credit or debit card payments without the monthly fees usually associated with merchant accounts.

Free of contracts and setup fees, Verizon sells the Card Reader for $9.97, which includes a $10 Square credit to absorb the up-front cost.

Hassle free

After purchasing the Square Card Reader from Verizon and downloading the Square app, it takes only minutes to get set up from the comfort of your home or office.

The sign-up process includes linking a bank account, which is used to deposit funds for credit and debit card transactions swiped by the Card Reader.

Sellers pay a flat fee of 2.75 percent for swiped transactions or 3.5 percent plus 15 cents for manually entered sales, and funds are deposited within 24 hours.

Square is also eco-friendly: Buyers use the touchscreen to sign for purchases, and sellers even have the option of sending email or SMS text receipts to customers.