Is it the starter or the battery on my 2000 Ford Focus SE?

So I have a 2000 Ford Focus SE and it all first when someone was working on my car because they left the radio on. It killed my battery and when I jump started the car I I took it home. It needs more repair so I try to leave it parked. I tried to turn it on one night but it wouldn't start. I heard a clicking sound every time I turned the key. I got a jump and the car turned on. Two nights later I walked to my car to see if it would turn on and the fuse box had a clicking sound. The battery fully died on me. There was also corrosion on one of the battery wires. I tried to start it again but I got the same clicking sound and this time it wouldn't start. Someone told me it's the starter but I hear the clicking sound still so could it be the battery? The power pack I used was not charged all the way.

What car should I choose ford ka or ford focus?

Basically my parents have this ford focus and its coming up to my 17th birthday so they said I could have that car if I put some money towards it which i'm willing to do however a family friend who is a mechanic is selling a Ford ka and he thinks that is a better first car for me. The focus is diesel but I think the ka is petrol. Which one is cheaper, safer or better as a first car?

2012 ford focus problems

I have a 2012 ford focus. And for the last two days when driving the transmission would stop working and car would stay one, when step on peddle the car would rev, just wouldn't accelerate. Then it died out. Stopped the car then started it up again and would be fine. Tonight, car completely won't start. But gots juice. Had the battery and alternator checked and is good. Tried jumping it and nothing but everything is fully functioning lightes, radio etc. In the past when starting the car the it wouldn't start and I would jiggle the ignition and move the gear shift and would start. Tonight when it wouldn't start, the battery light came on with the check engine light and the oil light. Please help me figure this out. I don't have enough money for a diagnostic and to repair. I only have enough to repair, i hope!

What should be my first car?

So i'm 18 and got manual driving license from the first time i've been driving for 4 months and i believe i'm good drive…
i'm going for college and i'm going to be using that car so should i get new car or used one? Assuming its a new one my father is looking at Chevrolet cruze, i have looked on the internet and reviews say mazda3 or ford-focus is better choice my father said ford are **** and not good and he doesn't like mazda (he wants cruze) what do you think?
Or should i get used car for the same price (old bmw or mustang) :P

Cheaper means of transportation?

So basically the insurance rates in new jersey are so ridiculous i can't afford to finance a car (witch i would have to do to get a new one since mine is near death) because of you needing comp and collision for basically any car is nearly 400$ a month from multiple companies. Its totally outrageous i don't know how any 20 year old like myself can afford that and have a reliable means of transportation. Public transportation isn't really an option for me seeing as my mom doesn't drive so anytime her or my little sister have a doctors appointment or need anything i'm the one who goes and gets it for them. Also i work varying shifts so that also makes things weird, basically needing my own transportation.

I know a motorcycle is an option but seeing as i can't really drive it in the winter or in the storms (it seems to rain 3 times a week anymore) it isn't really a realistic choice for me either.

Does anyone have any helpful insight of anyway i can either cut the insurance cost by nearly half to finance something or just another type of vehicle to drive?

Btw the cars i was getting quoted for weren't sports cars either they were just you're basic affordable sedans. Ford focus Kia forte Subaru impreza and things like that. The insurance cost is nearly double of the cost to finance the car. With my parents to cosign for me plus with bonus discounts the car is like 250 a month and the insurance is 380-475 depending on the car and company. Sometime please help me out here.