Good deal or not??

[David Carter]

I'm interested in a triplex near a college for 100k. A triplex down the street is renting for 455 a unit. These are the numbers I used to calculate cashflow. Mortgage is 665.30 for 100k at 7%.
Ins. is 83 a month
tax is 100 a month
10% vacancies is 137
10% for management is 137
After all that I get a cashflow of about 243 a month. Is this a good deal or not. I feel like I used conservative numbers but I'm not sure as I am new to this. Any input would be appreciated. I would probably save most of that 243 for repairs. I have a good amount of cash in the bank as a reserve and may put down a deposit if the bank requires it. I think the house is valued at around 140K. But again, I'm new, not sure. Thx