Anyone know anything about secured credit cards?

So backstory: At 19 I got my first credit card at Victoria’s Secret which at the time was my favorite store. Didn’t know much about credit. Was irresponsible and impulsive and totally destroyed my credit. I maxed it out within 2 weeks and then literally didn’t pay for like a year. At the time I had also moved out of my moms and started renting with my boyfriend st the time now husband so I was in a situation where I had no extra money each month to pay it back. I know, irresponsible. They ended up sending it to some other agency thing and cancelling my VS card. I paid off everything I owed and that was that I didn’t want another card after that because I felt I wasn’t responsible enough to own one and I wanted to make more before getting a new one.

Well fast forward I’m now 21 and I have educated myself a ton about credit, interest rates, paying back in time etc. I have lived with my husband for years now and haven’t been late on a bill in the last 2 years. I make more money and I feel I’m now financially ready to have a credit card and actually pay it back on time. I don’t even want to attempt to apply for any unsecured cards (regular credit cards) because my credit score is only 540 something and I don’t want to make it go down even more by applying for cards and not getting approved. So I was thinking about a secured card? Does anyone know anything about these? From what I have seen, I basically put down a deposit and then that’s how much I have? I was thinking about getting one putting down a $300 deposit or whatever the minimum deposit is, and then only using it for gas in my car. Like when I get it I will use it to fill my gas tank up, and then the next week pay it back and do it again and pay it back etc etc each week. Would that build my credit??? I really want my credit in the 700’s in the next 2-3 years because that’s when I will be out of college and my husband and I will want to buy a house instead of rent... Is that doable? Sorry if this is confusing. I never learned anything about credit growing up so I’m behind and I’m trying to figure it all out now because I know I need good credit.