Your 10GB Gen 5 plan is indeed $49.99, however, you are also billed an additional $14.99 lease fee for the modem, as well as a Property Tax Surcharge at approx. 75 cents...PLUS any applicable sales taxes.
Your entire bill will be approx. $66.95 (a little less or a little more depending on the taxes in your state)
If you go into your account settings, click on My Bill, and then scroll down to invoices, you will see a detailed invoice on the charges...
Make sure to open up each section for a complete breakdown/explanation.
Unless you make changes to your package, your bill will be the same each month.
To the original poster (not going to use his/her name),
You should immediately go in and change your Community name, or create a new Community name and cancel that one, as that DSS number is your account number, which you should NEVER post.
Not sure why, but apparently the OP has since changed their username after posting their initial question because this certainly wasn't the username that was attached to the original question when I replied with my answer.
Yes, you are correct that your service plan is $49.99. However this does not include the equipment lease fee, which is $14.99 nor local/state taxes. I hope I was able to clear that up for you. I've also changed your username from your account number to something more generic