1/4" sockets are very useful. I would recommend 3 sets whuch include 4mm, 5mm, 5.5mm, 6mm, 6.5mm-15mm.
1. Shallow well
2. mid-length
3. Deep well
Check out Sunex brand, they offer a great bang for buck. When I started out I wish someone would have steered me towards something other than the big three, Snap-on, Mac, and Matco. They all turn the same, you won't be beholden to the tool truck drivers, and you will save a ton of money, which with you being relatively young, i would recommend to start to invest as much as you can early on. Also, DO NOT allow any one individual handle your money. Start your own stock account, and give no one access to it, and i mean no one.
But I digress, If you have to choose one set, metric or standard, I would go with a metric set.
Go to Amazon, and type in 1/4" Sunex socket set, and you will find a set that includes, shallow and deep well, in both standard and metric for around $75-$100. I just purchased this set, and it is an excellent set, on par with the big three, and i would guess, you would have to pay between $750-$1,000 for this set. I have quite a few Sunex sockets, and i like them every bit as much as my Mac and Snap-on, actually even more so, because I saved a great deal of money.
Now if you think that you should buy off the tool truck, because they let you make payments, then you're starting down a road which is better less traveled. IOW, you will always have that payment hanging over your head, so you will just keep buying from them.
Payments don't have to be a necessary part of your life. You could outfit very nice HF $699 bottom box with Sunex tools or Craftsman, Gearwrench, etc for $5k including the box.
People on GJ will guide you to the things you will need to start. You have an amazing resource here, which most of us didn't have when we started out, bc of no internet. Buy the tool that you need most and a brand you won't have to make payments on.
Just some advice from someone that don't want to see young people start out in the hole.
So, to start with, get the set of Sunex 1/4" master set i mentioned above, a 3/8 and 1/2 master set too. You should be able to get into all 3 of these for under $500. That will prevent you from having to ask to borrow tools, which will get tiring for you as well as the techs you are borrowing from.
Keep asking questions, you will get a ton of respect, as a young person, if you show you want to learn, both here and at work.
Regards.
I forgot to mention, buy impact sockets first, those are dual use in both impact and non impact situations. Buy 1/4" 1st, 1/2" 2nd, and 3/8" 3rd, if you can't purchase purchase them all at once.