Welcome to Cardschat as this looks like your first post. My suggestion would be to make the quality posts so that you can play in
freerolls everyday associated with Cardschat. They are different from your average freeroll in the sense there are some better players but also still some typical freeroll players. The advantage is they are daily and the fields are smaller.
As far as success building a bankroll from freerolls only... yes you can do it but dont expect multiple thousand of dollar bankroll and dont expect it to happen overnight. My suggestion if you are going to go this route is to build a bankroll of $15 or so and then start playing $1 or less tournaments but dont start playing buy in tournaments with less than that. Get somewhat of a roll where you know you can bounce from this tournament and still play other buy in tournaments if you want. This way you play more normal instead of nit life-ing thinking you have to cash this tournament or x % of your roll is gone. You will have to be patient with the process if this is the road you want to go down but it can be done, it just takes time.
I've never deposited on ACR either but my bankroll is also nothing to brag about. I mostly play micros with an occasional stab here or there because I dont play poker to make money (I am not good enough) but play more for fun and recreation and whatever money comes from it no matter how small is a bonus.
If you are looking to use poker as an income source then I think you will need to deposit money and start playing larger tournaments otherwise you will spin your wheels so to speak and take a lot of time building any kind of decent roll off just freerolls. You need to define to yourself the reason why you are playing
online poker and then from there you make the right decision about playing freerolls and not depositing.