Yes, there is more to it.
Here's how it works. If you are at least 18 years old, have good credit, and have a steady and sufficient income, you can probably get a car loan on your own. As a young driver, don't even think about leasing, which is the deal you saw for $304. Loan payments for the same car are going to be higher.
You can get your loan at your local bank or credit union, or you can let the dealer handle it with his own finance company on your behalf. You make payments to the bank or finance company, not the dealer.
If you are not 18 and/or you don't have a good steady and sufficient income, your mom will have to buy the car in her name. You will not be on the contract or be a "co-signer." You can make payments if you can, but the car will belong to your mom.
If your only problem is your credit and you are 18 or older, and you have a good income, then you might be able to get a loan if your mom co-signs with you. However, she should understand the responsibility that she is taking on. The loan shows up on both your and her credit histories as an outstanding debt. If you stop paying, your mom must step in and begin making payments. If both of you stop paying, the car will be repossessed and you'll be sued for the loan balance after the car has been sold at auction.