<prompt> Human: I went to my local credit union where I already have a checking, saving and money market account. I want to build up my credit score, so I went in today to ask whether or not I could get a credit card. Ive had access to a credit card for two years; Im a joint cardholder with my father and have used it for emergencies, and my father always pays it off on time. However, I cant use this card very often or for personal expenses, so I wanted to get a credit card I can use for groceries or luxury items.However, the woman I spoke to said I did not have good enough credit to open up a normal card, leading me to ask what the point was of using my other card. She said I could not get an unsecured card due to the high risk, but I could get a secured card.Getting a secured card requires me to deposit 125 of the credit limit 625 for my 500 limit, and if at the end of my trial run I prove to be a reliable borrower I get my money back and can receive an unsecured card.Also, the woman warned me that if I get a credit card, I should never pay my balance off in full because then I wont improve my credit score. For example, if I put 300 on my card one month, then I should only pay 200 off, leaving the other 100 to gain interest.I dont know if Im being offered a good deal here, but Im new to the world of credit and cant really speak from experience. Do you think getting this card would make sense or not?  <response>: Also, the woman warned me that if I get a credit card, I should never pay my balance off in full because then I wont improve my credit score. For example, if I put 300 on my card one month, then I should only pay 200 off, leaving the other 100 to gain interest.This is bad advice and will cost you money.Wait until the statement arrives and shows a balance due, then pay that balance. That way card utilization still gets reported, but youre not paying interest.Otherwise, a secured card like this is a good way to get your foot in the door and start building your own credit. Just dont miss payments or carry a balance. An easy way is to set up monthly automatic payments. 