do you own a mn yourself if i may ask? and do you know about the hidden costs? hardware and monthly costs ?
Whatever you do you have the cost of the 10k coins, of course.
If you host your MN locally, your cost is the power consumed by leaving a computer running 24/7 (and the cost of the computer itself).
If you use a VPS, it will range in price. I use mp-hosting, and it's $1.80/mo for each MN. Others have had good results with a variety of options (e.g., vultr or the options avitas mentioned). Since my linux skills are rudimentary, I find that $1.80/mo is a nice balance--they set up the server, but I manage the MN. Recently each MN makes $3-5/day anyway.
There are no other hidden costs, unless you count the trivial transfer fees when you move coins around.