As someone with experience raising my ACR bankroll from $0 to $5k USD, this is what I did.
Play all freerolls. It's free money.
There is a leaderboard for the $10 freerolls on ACR. Top 10 get a $55 satty to the $1k cage. I've gotten into the $1k cage twice; no cash the first time, but a 3.8k score the second time.
Top 1 on the leaderboard also gets $215 Sunday Ticket, usually for the 50k GTD they have later on Sunday. I never cashed on those.
When it comes to buying into tournaments, follow some simple bankroll management rules.
When you have 100x the buyin, you can buy in.
When you have 5x the GTD, it's not worth buying in.
If the GTD to buy in ratio is less than 150, it's not worth buying in.
Happy hunting.