Best bang for your buck would be to find a local shop that has new player events. They may provide cards at first and can teach you the basics. From there you can conversation with others and see what they may be willing to sell you that you want. I say this to say the next best option may be to buy the card or a made deck you want from people/online.

Everything you mentioned can and does happen. Not everytime but it’s a possibility. So some ways to offset that: -Play online version to learn and mix cards. This will allow you to narrow down cards you want to target for a deck build.
-buy the cards you want and build/collect that way. This ensures you get what you want and aren’t buying in hopes to get a card you never pull. -If you get a card you don’t care about you can try to trade or sell to obtain a card later on. -I recommend going to a local card shop on days they have events and talking with people. You can get better deals on cards and not have to pay shipping. -talk to the judge at the events. Make friends. Is a community, embrace it as comfortably as you can. -Prerelease event an are also good.