No reason to stick with one champ. There are 105 for a reason.

If I don't stick one or a couple how do I get good in any?

Anything below 500 total wins in new/inexperienced, (including ranked)

Just keep playing all the champions, your to new to pick your favourite role, when I started I loved ADC and corki, now I only play mid and have a great position as a mid for a team.

You cant really stick to one champ if you expect to be anywhere near decent but its fine for just learning the game. However once you are more comfortable you should branch out to other roles and champs. You should at least be able to understand every role and play them decently.

Any champ suggestions? Preferably cheap ones.

I have the opposite problem. Any time I try a new champ, I end up playing really ****ty and going back to the one champ that I've been able to consistantly carry the whole team with, Garen *stares away lovingly in thought of that sexy beast*. I would recommend garen for your playstyle, he has insane amount of survivability and dmg in one champ.