That is $15 and below that you can pay by check?

Check out:

000Domains.com

I've never used them, I use GoDaddy (cc only) but they meet your request:

$13.50 per year and...

What forms of payment do you accept?
We accept credit card payments with VISA, MasterCard, American Express, or Discover Card. With a credit card payment your registration will be completed instantly.

If you would like to pay with a check or money order please make it payable to "000Domains.com" and mail to the following address along with your domain name and registration info (full name, address, phone, email, and your choice of username/password). If you have already registered a domain name with us, you can just send the previous domain name, username and password. Missing info will cause further delay. Make sure you are requesting an available domain name. Please note that by the time we receive and process your payment there is a chance the requested domain name could be taken.
R & K, Inc./000Domains.com
13200 West Markham St., Suite 104
Little Rock, AR 72211
000Domains (http://www.000domains.com/)

godaddy.com

or try register.com high price but very high quality

I use GoDaddy, they're great but they don't accept payments via check only credit cards. Steven was looking for domains under $15 plus that let him pay by check. The only I know of is 000Domains.com. I've never used 000Domains but have seen positive posts on WHT.

From GoDaddy:
Question
What methods of payment does Go Daddy accept?

Answer
Currently, Go Daddy only accepts credit cards for any of the services we offer. This streamlines our billing process so we can offer you the lowest prices possible for our services.

Go Daddy accepts these major credit cards:

Visa
Mastercard
American Express
Discover

We do not take these forms of payment at this time:

Cash
Check
Money Order
Paypal
Wire transfer or bank transfer