Agree with Russell that there are no "hidden" charges. You need to pay the usual closing costs, transfer taxes, title insurance, etc.
Hard to find profitable deals? Yes, but not impossible at least in Baltimore county. I just closed (8/21) on a 3 level end unit townhome (3 bed, 4 bath) in Owings Mills. All in, including closing costs and title insurance, was $192K. Rehab is $22K. ARV is $265-$273K. I'm a realtor and don't pay myself a commission so this flip will be very profitable.
Granted, I lost a few nights sleep worrying about it because I put a non-refundable EMD without seeing it in person on 4/3 in the middle of the COVID uncertainty and media hype. Wholesaler's deal with seller was that she had as much time as she wanted to move and could leave anything behind. That's why we didn't close until August. Took 2 days (and a 3 ton dumpster!) to clean it out, but I'll have it on the market mid-late September.