this happen to me a few months back, and guess what i'm back at again

I've got about 6k i would like to deposit this time. Probably 2 $3000 dollar checks. Once i receive the checks, I'm going to deposit straight into the atm. My worries are. How much do I need to deposit before my bank sends their shit to the IRS stating I deposited a large sum of money? Also I only make about 1200 dollars a month, and will putting 6k in a short period of time put up any red flags. I would much rather just do a bank wire but my credit union doesnt have a swift code or whatever you call it. Came here first to see what i should do.
