There is no credit check performed when determining eligibility for Stafford loans, so you do not need good credit to get one.
You must be an American citizen, national or permanent non-resident to apply. To apply, you must complete the Free Application for Federal Student Aid, or FAFSA, which requires you to fill out information about your finances and, if you are still a dependent on your parents' tax returns, their finances as well.
If you are determined to have a certain level of financial need, you may be awarded subsidized Stafford loans. The government pays the interest while you are attending school.
If you take out unsubsidized loans, you are responsible for the interest on the loan when you are in school. You can chose to make interest-only payments or you can allow the interest to accrue until you leave school.
Subsidized loans are capped at $3,500 for your first year, $4,500 for your second year and $5,500 for each year after that. The total amount of Stafford loans, subsidized and unsubsidized, depends on whether you are listed as a dependent on someone's tax returns. If you are, the limit is $5,500 for the first year, $6,500 for the second year and $7,500 for each year after. If you are not, the total limit is $9,500 for the first year, $10,500 for the second year, and $12,500 for each year after that.