A: HIV tests in the US are pretty reliable, so if the test was negative, it very likely is negative. There is a very small chance the test could have been wrong, but again the likelihood is remote. Just for piece of mind, find a local health fair or public health clinic that offers free testing and get a free rapid test. This will alleviate your concern about the money part,and the test is quick, so not a lot of time expended either.
If you are celibate, don’t get tatoos at tatoo parlors, and haven’t had a needle stick (e.g. from working in a hospital or clinic), you shouldn’t have to worry about HIV or STD’s. Your doctor or health clinic can perform a urine screen that tests for DNA of organisms that can cause STD’s and they can also do a culture. STD’s can sometimes not produce symptoms, especially in women.
If you haven’t had an STD test done, you can get one and you should be good to go if you’re not having sex. You shouldn’t have to repeat the tests until you become sexually active. Be sure to use barrier protection (male or female condoms) when you do.